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Blood Sweat Tears and Grease => Projects => Restorations => Topic started by: Jimbonaut on Jul 18, 2018, 16:34:29

Title: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jul 18, 2018, 16:34:29
Found this online after a couple of beers (how many build threads start with that sentence?) -

(https://i.imgur.com/T2nMwkf.jpg)
(https://i.imgur.com/RcDTR0t.jpg)

- after sticking my finger through the rusty gas tank and finding a 25th generation rats (?) nest in the airbox I made it mine for about $250.  Lovely guy, and at that price he literally made me buy it.  Despite a few...incongruities it looks pretty solid, tank notwithstanding. 

1982 CB750F apparently.  I thought it was the K model judging by the side panels but as I am starting to learn you should never judge a bike by its covers.  The seat looks original but the gap between that and the tank suggests the tank is from a different model CB750.  A previous owner has also ditched the stock pegs and levers for a rather intricate forward control/floorboard set up with crash bars - all heading for an online auction site near you soon.  It's a bit weird - the bike's an F but from what I can tell has been made to look like a K.  Hoping the fact that it's an F (sport model) won't mean it'll cost more to plate here in Quebec?  Could be a snafu, hope not.

Anyway, plan is to not do a Rhonda on this one, and therefore this thread finds itself in this section.  Amazing how comfortable this bike is in its (almost) stock duds - the seat, the bars - all nice and ergonomically very pleasing.  So in the spirit of my newfound desire not to bother my osteopath every time I go for a ride on the brat, this build will see a more comfortable, more sensible and dare I say practical (my 20 year old self shudders while my middle-aged self nods in approval of such mature considerations) CB750.

Of course that plan could all go down the shitter quicker than a fart in a fan factory, remains to be seen.

Any and all input on the F model would be fantastic, as would any takes on why this bike may have been reformatted into a different spec'd CB750 (at least in outward appearance).

Itching to get started.  It's going to be green.  Very, very green. 
Title: Re: 1982 CB750F Resto Mod. At least that's the current plan.
Post by: advCo on Jul 18, 2018, 16:54:22
I'm in. Looks like a nice Kerker on there. Bet you could carry plenty o' beers in that luggage too.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: farmer92 on Jul 18, 2018, 20:05:18
https://saaq.gouv.qc.ca/fileadmin/documents/publications/liste-motos-risque-eleve.pdf

Hereís the list of ďat riskĒ bikes at the saaq
Basically cbrís, gsxrís etc
Starting in 1985

I know a guy with (literally) a barn full of old tanks and bikes and anything you could ever want for a bike, just pm me if you want his #
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Jul 18, 2018, 20:53:46
https://saaq.gouv.qc.ca/fileadmin/documents/publications/liste-motos-risque-eleve.pdf

Hereís the list of ďat riskĒ bikes at the saaq
Basically cbrís, gsxrís etc
Starting in 1985

I know a guy with (literally) a barn full of old tanks and bikes and anything you could ever want for a bike, just pm me if you want his #

I'll take that number my man, thanks a lot
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Jul 18, 2018, 21:25:29
Apparently beer gets me trikes with death wishes.  Love the build, my man.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Hurco550 on Jul 18, 2018, 22:19:16
Apparently beer gets me trikes with death wishes.  Love the build, my man.
And instantly regrettable xt350's. (You can say you were drunk, even if you weren't) lol

And I'm in jimbo. Always enjoy watching your projects!

Sent from my SM-G920V using Tapatalk

Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: canyoncarver on Jul 19, 2018, 01:00:15
I had an 82' CB750F project at one point but I passed it on.  I'd have it back if I could.  I really dig the saddlebag setup on yours. Make it your own Jimbo.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Maritime on Jul 26, 2018, 16:21:44
Cool. I missed this, now signing up!
Title: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Jul 26, 2018, 16:42:07
Welcome one and all, bugger all to report other than I plan to switch out the tank/carbs/battery etc with Rhonda's (my other CB750) and see if I can't breathe some life into this old girl.  Anyone need a seat from an F model CB750?  Seems to be in good shape, along with the, er, scaffolding that's holding up the saddlebags.  All manner of peripherals on this thing - it'll feel archaelogical getting her kit off.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: advCo on Jul 27, 2018, 09:25:51
Welcome one and all, bugger all to report other than I plan to switch out the tank/carbs/battery etc with Rhonda's (my other CB750) and see if I can't breathe some life into this old girl.  Anyone need a seat from an F model CB750?  Seems to be in good shape, along with the, er, scaffolding that's holding up the saddlebags.  All manner of peripherals on this thing - it'll feel archaelogical getting her kit off.

Jim when you pull the bags off I may be interested in the bracketry holding them on. Post up some pics or send em over my way. I'd like to replace the crappy homemade ones on the BMW
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Jul 27, 2018, 12:02:20
Absolutely - hoping to tear into it this weekend so I'll post up some pics.  If they work for you mate they're yours for an al pastor and cerveza next time I'm in Texas =)
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: advCo on Jul 27, 2018, 12:57:49
Absolutely - hoping to tear into it this weekend so I'll post up some pics.  If they work for you mate they're yours for an al pastor and cerveza next time I'm in Texas =)

Well that I can gladly oblige
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Jul 30, 2018, 13:31:30
Ok, pitter patter let's get at 'er.

The bike's a non-runner so the plan is to pull and clean the carbs (a once-over at this point), switch out the tank with my other CB750, sling in some new spark plugs and see if I can get her started.  Before doing that I pulled the timing cover, got a 17mm socket on the crank bolt and turned it counter-clockwise - all the pistons are moving freely so they're not seized and that's good.

Cleared the way to the engine by removing the floorboards/forward controls/crash bars and pulled the carbs.  Here's the now-ubiquitous carb hero shot -
 
(https://i.imgur.com/vjqqhUW.jpg)

Getting into them it was clear that this bike has sat for a very long time.  The varnish was thick, black and everywhere.  Most of the main jets were completely blocked and this vacuum slide was completely seized -

(https://i.imgur.com/zbDgGNy.jpg)

- a few love-taps with a rubber mallet got it freed it but boy was it a mess in there.  Cleaned it up with some eau du carb cleaner and a rub with some 2000 grit sandpaper - now all four slides are moving as they should.  The carbs were disassembled to the point where I could blow carb cleaner though most of the ports, but I'll wait until the bike's running before completely disassembling the rack and getting all Pinesol on their grubby ass.  For now I just want to get the thing breathing smoke.

The choke butterfly's are in horrendous shape -

(https://i.imgur.com/ZLIcQf4.jpg)

- how in the world do these things rust?  Am I right in thinking these are for the bin, or can I clean them up to the point where they're salvageable?  The things look like Faces of the Damned - each portraying its own sentiment of anguish and despair.  Frightening.

This pockmarked monstrosity is the tank-shaped rust bucket that's soon for the dump -

(https://i.imgur.com/Nx19SSr.jpg)

- sitting alongside is Rhonda's tank that'll be the stand in while I try to get it fired up.  I'm also going to re-clear Rhonda's tank but that's for another thread.  Here's the state of the workbench as of Saturday -

(https://i.imgur.com/OFTSE2l.jpg)

and here's the bike -

(https://i.imgur.com/0rmyzfE.jpg)

Hoping to get the carbs rebuilt and back in the bike, sling the tank on and see what gives.  Here in Quebec any bike that's been off the road for more than a year has to go through a safety inspection - before I start chopping into this one I'm going to get it through that inspection first.

Pretty sure I'm going to call this bike The Upsetter.  For reasons that may or may not become clear.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Jul 30, 2018, 14:14:58
I'll get some photos up as well of all the gubbinery that I pull off the bike and won't need (crash bars, front fairing, forward controls, boards, rear scaffolding/bags etc) and most of which I'll give away to whoever can make use of it.  Advco's got dibs on the rear end stuff but anything else is up for grabs.  Should note that I'm in Montreal so bear in mind the shipping but other than that it's all yours.

I'm on the look out for some footpegs and levers - if anyone has any or could point me in the right direction that would be terrific.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Maritime on Jul 30, 2018, 15:38:16
Jim once you know what you're sending Nick, it may work best for you and him if you bus it to me and I drive over to Maine and send it to TX. We can look at that when the time comes.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Jul 30, 2018, 15:52:25
Jim once you know what you're sending Nick, it may work best for you and him if you bus it to me and I drive over to Maine and send it to TX. We can look at that when the time comes.

Mike Maritime - cementing his Legend status one post at a time  8)

Good man, can't thank you enough.  Unless several beers next time you're in town work in which case I totally can  ;D
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Maritime on Jul 30, 2018, 16:00:18
Ha, sure that sounds good.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: advCo on Jul 30, 2018, 16:01:04
Wow that tank was pretty rough, eh? looks like its got the chicken pox.

Appreciate the help if those racks work out, Mike.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Maritime on Jul 30, 2018, 16:11:08
Could save you $20 or more depending on size of box. I'd hate for UPS or Canada Post to get that extra LOL.
Title: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Jul 30, 2018, 23:36:26
Drained some of the oil, wasn't milky or weird smelling and tried setting setting it on fire but didn't light so pretty sure there's no gas in there.  Rebuilt the carbs, jammed them back in the bike and hooked up Rhonda's tank as a stand-in.  Don't mind the enormous fairing up front, slung that on for shits and giggles...

https://youtu.be/-EHuxVzExoc

Getting a non-runner to start for the first time is a feeling like no other.  Love it.  Took a while to fire, but that's because (I think) of the empty float bowls and vacuum petcock set-up.  You may be able to see the can sitting on the frame - that's Honda carb/combustion chamber cleaner and it's good stuff.  Much thicker than regular carb cleaner which - for whatever reason - works really well (guess it sticks around longer, burns slower?).  Either way, with the airbox not connected to the carbs and a good 5-10 seconds of that stuff sprayed into the carb body and it's off to the races.

The bike sounds pretty damn good too, no weird rattles, clanks or leaks yet.  Did see that one of the spark plug threads is cross-threaded so I guess I'm going to have to pull the head and re-tap it or get a TimeSert in there .  Other than that, so far, so good.  Will check compression tomorrow, but all four pipes were nice and hot (ie totally burnt myself on all of them) - including the cylinder with the cross-threaded spark plug.

Included in the vid is a close up of the air filter housing.  Me and my wife have a jewelry business - if I find a skull in amongst the rats nest in there I'm casting it in bronze and it's going on this bike.

Sweet.  So now that I know it runs I'm gonna do the basics on her to the point where she'll pass her safety inspection, then bring her home and get the grinders out.  Good people - onwards  8)
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Maritime on Jul 31, 2018, 08:25:54
Woot there it is. Good deal Jim. Looks like a full on project can commence now.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: advCo on Jul 31, 2018, 09:17:33
YEAH!
Title: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Jul 31, 2018, 22:54:52
Got all the scaffolding off the back of the bike, here's what I got up for grabs -

Front fairing -
(https://i.imgur.com/eyFGVf7.jpg)
(https://i.imgur.com/thPuefl.jpg)

Crash bars -
(https://i.imgur.com/ZpbcdQm.jpg)

Two floorboards -
(https://i.imgur.com/DhlSdNt.jpg)
(https://i.imgur.com/RAUuIeY.jpg)

Forward controls w/floorboards -
(https://i.imgur.com/0dc3Yff.jpg)

Saddlebags & bracket (maybe off a Rebel?) -
(https://i.imgur.com/qurcC4b.jpg)
(https://i.imgur.com/ZgwY4Ln.jpg)

Sissy bar (off a Rebel) -
(https://i.imgur.com/55B5Ozi.jpg)

Saddlebags & sissy bar may be spoken for - if it doesn't work out then like everything else it's all free, just cover postage (from here in Canada).  Lemme know =)

Picked up a tank today, it's taken one for the team but it should pop out (any suggestions on how to do that would be gratefully received) but inside is spotless, no rust or varnish at all.  And that means no MEK, and that's a wonderful thing.

(https://i.imgur.com/d2hJIa5.jpg)

It's a K model tank and that's fine by me.  Although the bike is an F, I prefer the styling and lines on the K tank and love the gold pinstripe.  Got a colour scheme in mind, and I'll definitely be incorporating that gold pinstripe into the design.

(https://i.imgur.com/O8WM6Sm.jpg)

Bike-like.

And here's what I pulled out of the air filter housing...

(https://i.imgur.com/P6n5BpM.jpg)

Gotta hand it to the little guy, that looked snug.  If I was a rodent shivering away in a Quebec winter I'd've made my crib as comfy as possible too.  Sorry fella, you're evicted.

Also checked compression today -
Cyl #1 - 165psi
Cyl #2 - 170psi
Cyl #3 - 165psi
Cyl #4 - 165psi

Pretty damn good.  I mean, shit - factory is 170psi +/- 14psi according to Clymers.  This thing's barely lost anything in 35 years.  Gotta hand it to those Japanese, they sure know how to build an engine.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: pidjones on Aug 01, 2018, 13:58:52
I've read that hot glue on a dowel rod can do wonders for popping such dents. No experience at it, however.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: advCo on Aug 01, 2018, 16:48:47
I've tried the hot glue but I think the bigger the surface you glue to it the better. Like a drink bottle with a bigger 1" cap, I think cbrianroll posted a pic of that in Hurco's TW200 thread now that I think of it.

Also heard of people using a sphygmomanometer inside the tank and inflating it, or baking soda and vinegar to pressurize the tank and pop out the dents that way (careful not to bust the seams)
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 06, 2018, 12:17:31
Well the orderly line of people queuing up by my garage door for a beat-up 80's era burgundy front fairing with missing indicator never happened.  Stunned silence?  I know I know.  I couldn't believe it either. 

Pulled the carbs out again now I know it fires, bench synched them, cleaned out the airbox and filter.  I've realized it's a hell of a lot easier to install (and remove) these carbs by only attaching one accelerator cable (the pull one, not the push one).  Of course both should be attached but I'm wondering if it's a complete no-no to leave the push cable off - temporarily.  I basically need to get this bike through a safety exam (hmm, ironic) and then will be pulling everything apart again for the build.  Bad idea?  If that cable snaps then I'll answer my own question in dramatic fashion I guess...
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 06, 2018, 12:18:59
Also heard of people using a sphygmomanometer
A who?
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 06, 2018, 12:42:57
Can anyone tell me if these carbs are stock?  Looking at Clymers it says (if I remember correctly) that the CB750F has either VB 42 A, B or C.  These are 42 E.  Anyone know what the difference is?

(https://i.imgur.com/drH1rvY.jpg)
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Aug 06, 2018, 13:08:20
82 CB750F should be VB42AG
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 06, 2018, 13:25:51
Cheers Irk. Any idea what the differences between the carbs are?


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Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: advCo on Aug 06, 2018, 13:40:20
A who?

(https://cdn.shopify.com/s/files/1/0268/9111/products/Sports_520_F.A_K_52443973c97bb_6e18f7cc-fe05-4a9f-ae20-7d90ffcf8e62_large.png?v=1465254772)
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 06, 2018, 13:44:07
So thatís what that thingís called. Learn something new every day 🧐


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Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: advCo on Aug 06, 2018, 13:45:30
So thatís what that thingís called. Learn something new every day 🧐


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I only know the name from looking it up for popping dents on a motorcycle tank  ;D
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 06, 2018, 13:59:29
I only know the name from looking it up for popping dents on a motorcycle tank  ;D
Better that than for spiking blood pressure


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Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Aug 06, 2018, 14:24:34
Cheers Irk. Any idea what the differences between the carbs are?


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Hard to say.  I've never see anything about your particular E carbs.  They might be Euro spec or something, but all the VB42 carbs (in the US) are jetted the same and share common specs on paper:

3 Jet Vacuum Slide:

EPA Spec (US), Hidden Emulsion Type Idle Mixture Screw, Non-Replaceable Slow Speed Jet (Some Models) Non-Adjustable Jet Needle (All Models) Air Cut Valves (All Models), Twin Sequentially Functioning Main Jets (68/102), Slow Speed/Pilot Jet (35), Accelerator Pump (All Models)
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 06, 2018, 14:30:48
Cheers man - from what I've read the number after VB (in this case 42) refers to the size of the venturi.  Jets-wise, these carbs have been fitted with 68 primary and 100 secondary.  But the Clymers indicates the F should have 102 I think.

"Dabbled with" definitely applies to this bike.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Aug 06, 2018, 14:36:38
Cheers man - from what I've read the number after VB (in this case 42) refers to the size of the venturi.  Jets-wise, these carbs have been fitted with 68 primary and 100 secondary.  But the Clymers indicates the F should have 102 I think.

"Dabbled with" definitely applies to this bike.
That's correct.  It's always Venturi size at the slide.  And definitely should have a 68/102 in stock form.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 06, 2018, 14:48:42
The bike has a 4 into 1 Kerker exhaust - may that be why the jetting has been adjusted?
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 06, 2018, 23:21:29
Carb hose question - when I pulled the carbs, both hose A and hose B were connected to the carb body at one end but not the other -

(https://i.imgur.com/9QH0Ldg.jpg)

here's another shot -

(https://i.imgur.com/7yYpDSd.jpg?1)

But on my other CB750 there's only one hose that's connected to both ports on the carb.  So I did the same with this, ditched one tube and looped the other -

(https://i.imgur.com/OSeIWtC.jpg?1)

Is that correct?

Hooked up the carbs, tank, airbox again, fired it up - seems to idle ok but as soon as I crack the throttle the revs stay high.  I checked all the boots to see if there was a vacuum leak but they seem ok, and the throttle cable isn't binding.  Any ideas what could be causing this?
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Aug 06, 2018, 23:44:30
That's your automatic fuel valve.

(https://i.imgur.com/7yYpDSd.jpg?1)

The tube in your fingers is an air line.  The tube in your thumb is a vacuum line.  Your high idle sounds like maybe the carb is running out of fuel and going lean.
Title: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 07, 2018, 00:02:15
So I shouldnít loop one hose like I did? Both hoses should be connected to the carb and open at their other ends? Strange if not, because that hose is looped on my other CB


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Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Aug 07, 2018, 00:40:43
(https://images.cmsnl.com/img/partslists/honda-cb750f-750-super-sport-1981-b-usa-automatic-fuel-valve-81-82_bighu0129e5z19_8cbf.gif)
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 07, 2018, 01:03:29
Man thatís really helpful - thanks mate. Iíll re-route those hoses and see what gives.

Really weird though. Guess the other CB threw me with its hoses and their routing. Could that routing be so different?


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Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Aug 07, 2018, 08:37:50
I have no idea.  Maybe a seal leaks on the other one, so it pulls air through the seal and seems routed right.  Funny things happen. When I got my 1979 C10 from my dad, it started making a clicking sound while I drove the 2.5 hours home.  It ran and drove fine, just made that sound.  Turns out, my dad had the vacuum hoses routed wrong, so it was sucking air through the main seal.  He only drove it around his property and occasionally took a load of metal a couple miles up the road to the scrap yard, so the motor never heated up enough to do that for him.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 07, 2018, 11:42:37
Thing is Irk, that diagram shows four hoses but as it sits my carb has five -

(https://i.imgur.com/ZLIcQf4.jpg?1)

My (limited) understand would suggest that -

1. is a fuel line from the auto fuel cock to the carb body
2. not sure but I'm pretty sure it's in the right place
3. is a fuel line from the gas tank to the auto fuel cock
4. is a hose from the carb body (in between carb 2 & 3) to somewhere
5. is a hose from the auto fuel cock to ??

So I've got five hoses, but the diagram only shows 4.  Hose 4 and 5 are the mystery meat.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Aug 07, 2018, 11:55:40
Thing is Irk, that diagram shows four hoses but as it sits my carb has five -

(https://i.imgur.com/ZLIcQf4.jpg?1)


The diagram only shows hoses attached to the auto fuel valve.  What you have marked 4 doesn't go to the fuel valve, so it's not in that diagram.  I'm guessing that 4 is attached to a nipple on your #2 carb, which is the carb that holds the pumper.  As such, I'm also guessing that your pumper runs directly off the tank, and not through the auto fuel valve.  Just guessing by what I can see in the pics.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 07, 2018, 12:14:02
Ah, good catch.  So would that mean that line 4 would - along with line 3 - connect directly to the petcock on the gas tank? 
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Aug 07, 2018, 12:22:58
Ah, good catch.  So would that mean that line 4 would - along with line 3 - connect directly to the petcock on the gas tank?
Right
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 07, 2018, 12:28:57
If thatís the case then I think I smell a snafu. I canít tell from the VB number on these carbs where they originally come from, but I donít think theyíre from an F model. And now I have a K model tank. The petcock threads on the tank seem to be different for each model and year, and the only petcock I can find that fits this K tank only has one outlet.




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Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Aug 07, 2018, 12:37:31
If thatís the case then I think I smell a snafu. I canít tell from the VB number on these carbs where they originally come from, but I donít think theyíre from an F model. And now I have a K model tank. The petcock threads on the tank seem to be different for each model and year, and the only petcock I can find that fits this K tank only has one outlet.




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It appears the K and F share a part number on the petcock, so we know that's at least correct.     16950-MA4-771

What I do in parts searches is borrow Western Hills' site and do an OEM part search:

https://www.westernhillshondayamaha.com/index.htm
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Aug 07, 2018, 12:43:08
(https://images.cmsnl.com/img/partslists/honda-cb750f-750-super-sport-1981-b-usa-automatic-fuel-valve-81-82_bighu0129e5z19_8cbf.gif)

3 and 7 are fuel.
4 is vacuum
5 is air vent

Now to figure out what your 5th hose is.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 07, 2018, 12:51:10
Now to figure out what your 5th hose is.

Yup, that's the question mark alright.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 07, 2018, 13:14:15
Ok, may be getting somewhere.  Hose 4 is apparently a float bowl vent.  Hose 5 is vent for the auto fuel valve.  Stands to reason then that both these hoses should be open at the ends.  If perhaps one (or both) of them is blocked then that could be causing the problem I guess.

Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 07, 2018, 20:59:24
Trying, trying hard not to look at today as a total fail.  There's a lesson in there somewhere - just need to dig it out.  And I'm digging deep.

Pulled the carbs again, re-routed the hoses and double checked everything before putting them back in the bike.  Hooked up the gas tank, turned on the the petcock and smelt gas - carb one was pissing gas out of the overflow tube.  Thought maybe it was a stuck float valve - gave the side of the carb a whack with a rubber mallet but it still overflowed.  Figured fuck it - I'll try starting the bike and see what gives, and that was when problem two arrived.

The bike wouldn't fire, instead I heard a rapid clicking from the starter relay/solenoid and then a rather disconcerting mechanical clank from somewhere.  Killed it, thought maybe the 30A fuse had blown so switched it out with my other CB, to no avail.  Then switched out the whole starter relay/solenoid assembly with the other CB - still just a rapid clicking, another clank and that was all she wrote.

The bike fired up fine before I pulled the carbs.  Ran rough, but it fired.  I'm sure the starter problem doesn't have anything to do with the carb work I did but have no idea what to do or check next.

Any pointers?

Edited to add - I'm pretty sure it's not the battery as it was charged, but I have the thing on trickle anyway and will try it again in a few hours.  Could the clutch switch have something to do with it?  The bike is in neutral, at least the neutral light is on.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Aug 07, 2018, 21:10:09
What's battery voltage? 
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 07, 2018, 21:16:19
Battery voltage was about 11.9V
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Aug 07, 2018, 21:43:41
Battery voltage was about 11.9V
That's basically discharged.  Charge it up and try again.  If it doesn't hold charge, get you a new battery.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 07, 2018, 21:57:39
Cheers man, really appreciate the help as always. Had the battery on trickle and sure enough it fired up after dinner. I thought 11.9V sounded pretty much fully charged but I now know better.

Gas is still pissing out of carb 1. More rubber mallet whacks but no dice.


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Aug 07, 2018, 22:07:37
Try blowing through the fuel line from the tank.  If it's debris on the float, it may clean it off.  Works more than it doesn't.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 07, 2018, 22:13:31
Disconnect the fuel line from the gas tank and blow through the thing?  I'll give it a go mate.

When the bike did start it idled like absolute shite - the revs climbed and climbed until I was sure a disgruntled neighbour was going to launch a frying pan at my head.   :-\

I'm starting tho think these carbs may be in need of more than just a rudimentary clean.  So plan B will be to pull the carbs from the other CB and switch them out, just for long enough to get the bike through its safety exam. 
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 08, 2018, 21:10:55
Things are on the up. Pulled the tank and checked all the hoses, possible that the vacuum hose was a bit pinched, Iím not sure. Everything else looked kosher, nothing binding but I gave everything a good check.

Drained float bowl in carb 1, took the bowl off - everything looked alright in there but I pulled the float and needle anyway and gave them both a good clean, also blasted carb cleaner up into the needle seat.  As Irk suggested I also blew through the fuel line.

Hooked the tank up again, carb 1 leaked right away but once I fired up the engine it stopped and didnít leak again. Bikeís idling better, revs arenít going up by themselves like before - a little stuttery when I crack the throttle and release it (as the revs drop they donít do so smoothly but a bit juddery). Hereís a vid -

https://youtu.be/oiVI40OEzDc

Definite improvement


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Aug 08, 2018, 21:19:40
Awesome improvement.  Still hanging a bit on decel from the rev, but maybe just an air mix adjustment.
Title: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 08, 2018, 21:22:06
Cheers Irk, is that something that a decent vacuum synch would take care of? Or pilot screw adjustment?

Wetter than an otterís pocket here so at least the rain is drowning out my erratic engine somewhat. At least that what I like to think my neighbours are thinking.


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: trek97 on Aug 08, 2018, 22:20:38
You been busy my man.  Good show!  8)
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 09, 2018, 11:50:37
Thanks Trek, thankfully with the other CB in decent shape I can just borrow what I need from her (which is a lot!) as I try to get this beast in shape. Hopefully the carbs are in good enough shape (especially after a vacuum synch) to get this on the road soon - pass the safety inspection and then out with the power tools  8)
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: trek97 on Aug 09, 2018, 22:15:31
on the road soon - pass the safety inspection and then out with the power tools  8)

(http://www.dotheton.com/gallery/11494-090818201506.png)
Title: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 09, 2018, 23:27:27
Ha! Super powers or MEK-into-the-eyeball-significant-abilities...whichever comes first


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: trek97 on Aug 10, 2018, 08:58:14
Ha! Super powers or MEK-into-the-eyeball-significant-abilities...whichever comes first

Had my fair share of acetone nd lacquer thinner in the eyes...Although Ive recently started using MEK, I havent tried it yet.   :o 
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Aug 10, 2018, 12:42:56
The stuff is b-r-u-t-a-l.  Despite every best laid plan, most MEK adventures in my garage go south quite dramatically.  I do however always dress for the occasion and that's a good thing - this stuff will eat your soul and laugh as it spits out the dark parts.

Will it ever melt through varnish though.  Mamma mia.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Sep 10, 2018, 14:00:47
Not much been doing but that may change soon.  Still need to get the bike in shape enough to pass its safety exam, these'll help -

(https://i.imgur.com/cqy1v8L.jpg)

Avon Roadriders.  They look good, the reviews are glowing and I like the width of them too.  But it's the smell that's got me writing home - wonderful. 

Also picked a new starter relay up from a friend which will definitely help no end too -

(https://i.imgur.com/lwQkYix.jpg)



Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Maritime on Sep 10, 2018, 14:06:02
Nice, love roadriders.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Hurco550 on Sep 10, 2018, 14:20:17
Nice, love roadriders.

+1. have them on my gt250 and one on the front of the airhead. The tires have more grip than I have guts lol
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Sep 10, 2018, 14:27:29
My choice was pretty limited in terms of sizes for this bike - came down to Metzeler Lasertecs and a few others but for the money and the reviews I read these things are the business.  Good in rain, good on cracks and excellent on tar snakes.  I went for a ride on the KLR up into the hills a while back, hit two snakes going round a corner and totally lost the front end.  That's squeaky bum time right there, don't want to experience that again in a hurry.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Maritime on Sep 10, 2018, 14:41:39
+1. have them on my gt250 and one on the front of the airhead. The tires have more grip than I have guts lol

Exactly, I could not get to the limits of traction on them with my 450 and they lasted 3 seasons before I sold it. Shinkos stick too but I only get 1 season out of them
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Hurco550 on Sep 10, 2018, 14:58:18
Exactly, I could not get to the limits of traction on them with my 450 and they lasted 3 seasons before I sold it. Shinkos stick too but I only get 1 season out of them

yep, I have a shinko 712 out back, grips good enough, but will likely need replaced at the end of the season (depending on how many miles I can hammer out before the baby gets here haha)

Once I got the roadrider broke in, I hit up my usual tire test curve in the back of the neighborhood. There are very few houses back there, and even less traffic, plus the lot on the corner is clear cut so you can see clear through it for on coming traffic. I try to hit it at 5 m.p.h. higher increments and see how the tires feel. I shouldn't admit to how fast I hit the curve (in a 35 mph residential zone) lol before I felt the rear shinko "going". It felt like it was just on the verge of starting to wash, but the front with the roadrider held tight. Either way, I hit that curve way harder than I ever would in normal daily, or even spirited riding on a lesser known road.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Sep 10, 2018, 15:24:40
I know that curve.  ;)
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Hurco550 on Sep 11, 2018, 10:51:16
I know that curve.  ;)
One day when I went to work over the dr650 in that corner after changing fork oil weights, I rode down to find some gravel from the berm kicked out into the curve. I rode home, got a broom and was sweeping it off. I got a few funny looks from the few cars that did pass by while I was out there sweeping off the road by hand haha.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Hurco550 on Sep 11, 2018, 10:52:46
sorry for the thread jack jimbo. Here in ohio, we basically have like 3 curves in the entire state, so I have to talk about it ya know lol

back to your regularly scheduled programming ;)
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Sep 11, 2018, 10:55:48
Ha!  I hear you mate - here in Montreal we have 2 roads with no pot holes in.  They get talked about a lot too   ;D

Interestingly, I'm thinking of adding some longer spacers to the KLR forks - the front end seems a little plunge-y.  I thought about changing the oil weight but think I'll try the spacers first, see if I can stiffen things up a bit.

There.  Jacked my own thread.  *mic drop
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Sep 13, 2018, 10:30:07
Progress may be geologically slow (think glacier-moving-down-a-mountain slow) but progress nonetheless.  Wheels came off yesterday, hoping to get the new rubber on today.  Got myself a part-time job at a local motorcycle repair and custom shop so if I get in an hour or two earlier I can sling my own Avons on. 

(https://i.imgur.com/Pvoo4Vf.jpg)

What a difference a year makes.  This '82 CB (albeit an F) has a few noticeable upgrades to the '81 K, none more apparent (so far at least) than the brakes.  Not just dual discs up front and a disc out back, but sturdier caliper brackets too.  Guess I shouldn't be surprised (it's Honda Progress after all) but good to see all the same.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Sep 14, 2018, 11:32:17
Got into work a couple hours early yesterday - now that I know my way around the tire changing machine, slinging on my own rubber was certainly a first.  Big Red takes a bit of getting used to, but with the benefit of time on my hands the job's a good'un...

(https://i.imgur.com/4QyaUkc.jpg)

Not sure what looks better, the new-look wheels or the startlingly red hydrant -

(https://i.imgur.com/kpeTFxU.jpg)

Love me some new rubber.  Definitely a wider rear tire than Rhonda, dig the look and looking forward to getting the wheels back on the bike.  Hopefully got a long ride planned on Sunday but Saturdays plans are up in the air - need to do some work on Rhonda but also hoping to get this CB closer to her inspection.  Carbs need a vacuum synch and brakes need bleeding, but hoping everything else will be ok enough to squeak through the safety exam.  Then it's gloves-off time.

Avantť.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Maritime on Sep 14, 2018, 11:48:56
Nice. 
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Sep 24, 2018, 10:27:48
Got the wheels back on and started cleaning out the crud from the tank.  On first inspection it looked clean as a whistle but there is in fact some old gas and varnish (no rust though) so got the old nemesis MEK in there overnight doing its thing.  Plugged up the petcock hole with a rubber cork-type-thingy.  Hoping it's held, otherwise, well, bad things are happening in the garage as I write.

Once the wheels were back on I actuated both front and rear brakes - the front is working just fine but the rear caliper seems to have seized completely on the disc - I can barely move the wheel.  I'm thinking the best course of action is to crack the bleed valve, pry the caliper off and dismantle the thing for a proper clean.  It looks a little toasty.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Sep 24, 2018, 11:11:07
MEK is used to add patches, or bond, damaged urethane rubber by breaking down the outer layer and making it tacky.  A significant amount of MEK coming in contact with urethane rubber will completely dissolve it
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Sep 24, 2018, 11:15:22
Once Iíve got breakfast down me Iíll find out one way or another...


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Maritime on Sep 24, 2018, 11:17:09
Ha, it also melts ABS to make a slurry for repairs. Used it on the camper, going to do it again. Makes you dizzy if you forget the mask too.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Sep 24, 2018, 11:42:21
Makes you dizzy if you forget the mask too.
If by dizzy you mean total cranial meltdown then yeah, dizzy  :o
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Sep 24, 2018, 12:36:40
Wheels, on -

(https://i.imgur.com/zH2p0eC.jpg)

MEK, marinating -

(https://i.imgur.com/YIWA3fJ.jpg)

Rubber bung held up nicely, giving it another hour then draining the stuff.  Damn that stuff does not fuck around in any way whatsoever.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: irk miller on Sep 24, 2018, 13:18:34
Looking good.  Good thing on that MEK.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Sep 24, 2018, 14:57:44
Got the MEK out without any characteristic mishaps, so that was a first.  Man that stuff makes quick work of varnish.  Dumped 4 litres of gas in the tank to see if the petcock I salvaged was in decent shape - turns out it isn't, and I'm pretty sure these model petcocks aren't rebuildable.  So on the hunt for a replacement - remember this being a ball ache with the other CB so hoping not for a repeat of that.

Pretty happy with the state of the tank's insides - apart from a bit of rust and Montreal's unhappiest wasp very little else came out.

(https://i.imgur.com/g9C2fwK.jpg)
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: CrabsAndCylinders on Sep 24, 2018, 16:03:33
The return hole in the master cylinders on these bikes is small and can get blocked with crunge if the brake fluid is not changed regularly.  You can use a high E guitar string to clean it out.  This could be why your rear brake is seized but it could also be that the slave piston is seized.  Can you remove the rear wheel, if so you can use a grease gun to move the piston out if it is seized.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Oct 17, 2018, 10:54:47
Got the carbs vacuum synched and have to say the engine is humming along pretty sweetly.  There's what sounds like a chain rattle from inside which I'm hoping some cam chain tensioning will address, but other than that I'm pretty chirpy.

Big mistake I made was not installing an in-line fuel filter - the carbs (which have only been given a rudimentary clean at this point) are leaking like a sieve.  Gonna have to pull them again and give them a decent clean now that I've installed the filter and hope that'll do the job until I can get this thing through its safety exam.

Freed up the rear brake caliper a little but it's still clamping hard on the rotor - I think one of both of the pistons is sticking.  Gonna pull the caliper, free out the pistons and give the thing a decent clean, see if that'll do it.

Managed to get the thing out into the alley last night for its maiden voyage.  Best feeling ever, getting a non-starter to roll for the first time.  No seat, tank lifted from the other CB...ugly as a blind cobbler's thumb but sounds pretty good, even if it was spraying 91 octane all over Montreal's finest.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: pidjones on Oct 17, 2018, 11:38:13
Just in the final stages of reassembly on my '79 750F carbs. You're in for some fun! Inline filter is a must. There is a great manual in pdf form online to guide you through the rebuild - lots of photos and details. I think rev G is the latest. Still cleaning the inside of the tank on mine - been rolling it for a week with Evapo-rust in it. Begore that it sat with acetone for a couple weeks to remove the varnish left by over 15 year-old gas. Not really that much rust, however. It took a couple cans of spray carb cleaner and some guitar string in a pin vice to clear out all the varnish from carb passages and jets. The accelerator spray nozzles were real fun!
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Oct 17, 2018, 11:52:48
Man I love carbs.  Working on them is one of my favourite parts of the (re)build - I've worked on the the Keihin carbs before on my other '81 CB750 so I've got an idea of what to expect.  I closely followed Mike Nixon's really helpful booklet on how to clean and rebuild them which proved invaluable, and will follow it to a t again when I tear the bike down for a proper resto this winter.  Right now just kinda bodging it to squeak the thing through its safety.

For de-rusting my tank I used Metal Rescue - just dump a few litres of that stuff in the tank and I was amazed at how well it worked.  It needs to be warmed to work well.  I knocked off all the big stuff with a length of coarse chain too.  Good luck with the rest of your build mate, post a link to your build so I can have a look at what you're working on.  Go the F's!
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: pidjones on Oct 17, 2018, 19:50:55
Here is my build thread: http://www.dotheton.com/forum/index.php?topic=75909.0 (http://www.dotheton.com/forum/index.php?topic=75909.0) I think you will like today's post.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: trek97 on Oct 18, 2018, 10:25:50
Man I love carbs.  Working on them is one of my favourite parts of the (re)build -

Im with ya bud,  Carbs are just little miracles of engineering and design. 
To do what they do w nothing more than vacuum pressure is amazing.
The amount of education-math-R&D-trial and error over the generations all added up together, would probably be astounding.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Oct 18, 2018, 11:07:48
Here is my build thread: http://www.dotheton.com/forum/index.php?topic=75909.0 (http://www.dotheton.com/forum/index.php?topic=75909.0) I think you will like today's post.

Thanks for the link man, I'll be following along with great interest.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Oct 18, 2018, 11:17:50
Im with ya bud,  Carbs are just little miracles of engineering and design. 
To do what they do w nothing more than vacuum pressure is amazing.
The amount of education-math-R&D-trial and error over the generations all added up together, would probably be astounding.

Genius.  I'm still wrapping my head around the minutiae of the things but the more I dig into them the more I'm fascinated.  Much appreciation.

You wouldn't think it however if you saw the state of them right now - pissing octane all over my garage floor, arterial spray all over the ceiling.  Looks like a mechanical nightmare version of The Shining.  Need to get me some decent float bowl gaskets and clean up the float needles and jets again.  Teach me for rushing and not installing an inline fuel filter.  Lesson learned.

Finally got the rear brake caliper loose from the rotor - closer inspection revealed the rubber piston seals were all chewed up and preventing the pistons from moving.  Tried blowing them out with compressed air but that got me absolutely nowhere, so hooked the caliper back up to the brake line and forced the pistons out by actuating the brake lever.  One anyway, the other piston was jammed in there tight - took a wrassle with some pliers to get the thing out.  Got a rebuild kit on order.

Need me some float bowl gaskets but don't want to spend the earth on them - any ideas?
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: trek97 on Oct 18, 2018, 13:28:46
pissing octane all over my garage floor, arterial spray all over the ceiling.  Looks like a mechanical nightmare version of The Shining. 

Need me some float bowl gaskets but don't want to spend the earth on them - any ideas?

Hahaha ;D

Yeah 4into1 is your best bet.  My local Honda dealer has the complete o-ring set for your carbs...at $42.40 each.  ::)
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: trek97 on Oct 18, 2018, 13:40:33
https://www.nbc.com/saturday-night-live/video/the-french-chef/n8667


Oh and carb kits....$46 for all four not bad compared to $42 a piece. 
https://4into1.com/carburetor-rebuild-kit-set-of-4-honda-cb750f-super-sport-1980-1982/

If you're hoping the factory brass make sure to compare new w the originals to make sure new o-rings will properly fit the old stuff.

For mine, (400four) the float valve seats and the main jets were different diameters...had to go w the new parts so O-rings fit correctly.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Maritime on Oct 19, 2018, 07:51:44
Jim if need be I can get the bits out of Mine ans send them on the bus tonyou as well if shipping cross border is rediculous.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Oct 19, 2018, 14:51:59
You're a good man Mike, thanks man for the offer.  Should be ok though - I'm in the US week after next so I'll get anything I need shipped there.  By the way, haven't forgotten about that SharkHide - just keep kinda forgetting haha.  I'm on it.  Glad you're on the mend mate.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Oct 22, 2018, 12:07:25
Not much to report here either.  Still planning on squeaking the bike through its safety exam - all the work I'm doing on the bike at the moment therefore is on a kinda wing-and-a-prayer basis.  Which isn't a great plan of attack as it turns out.  Had to borrow a bunch of parts off Rhonda (starter relay, carb floats and gaskets, er, tank) but it's one step forward and two steps back.  So, Plan B.

Pulled the carbs again and will be ordering a set of new o-rings and gaskets.  The kit includes some new float needles - the ones I have a the moment look ok but the little spring pin is a bit stuck on some of them (is there any way to free that up?  I'd like to keep the originals if possible).  Installed an inline fuel filter and have a front brake caliper rebuild kit arriving soon too.

Still borrowing Rhonda's tank, but promised her she'll get it back asap.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Maritime on Oct 22, 2018, 13:51:46
You're a good man Mike, thanks man for the offer.  Should be ok though - I'm in the US week after next so I'll get anything I need shipped there.  By the way, haven't forgotten about that SharkHide - just keep kinda forgetting haha.  I'm on it.  Glad you're on the mend mate.

No worries Mate. hope all goes well with the inspection.

Cheers

Mike
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: farmer92 on Oct 22, 2018, 14:47:49
It wouldnít be quebec if he didnít have to do the inspection 2-3 times
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Oct 22, 2018, 15:01:18
It wouldnít be quebec if he didnít have to do the inspection 2-3 times

minimum...
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Dec 05, 2018, 12:55:04
Well, shit - so much for that.

This riding season just seemed to fall off a cliff - one day we could and the next the arse fell out of the weather and that was all she wrote.  My plan to get this bike thru its safety exam before introducing it to power tools was a massive fail so, well, balls to it.  Avantť.

Cleaned up my grenaded garage over the weekend, turned on the shop heater and had a good sit down - a couple of hours just looking at the bike is time well spent.  Have a few ideas percolating, ergos more or less figured out and a general plan of attack up my sleeve.  Let's see how far I deviate.

Here's where I'm at -

(https://i.imgur.com/2aaNglx.jpg)

Yeah, not much further than a few months back. 

Will be starting the tear down very soon, love that part.  Question, does anyone recognize these shocks?

(https://i.imgur.com/1A9lCdl.jpg)

They sound like they've got emphysema, really wheezy.  Are they rebuildable?  They're not progressive but seem to be otherwise in pretty good knick, might clean up nice and they're very adjustable too. 

If anyone needs any fog lights then hit me up - have a pair I pulled off this thing which I have no need for.  Can send a pic.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Maritime on Dec 05, 2018, 13:04:22
Ive got that same set of shocks on my GL. Not sure on the rebuildable part but they are better than the 79 GL ones I had. Justin sent me them off a 750 he parted out.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Dec 06, 2018, 10:10:39
Any idea what brand they are Mike?  Probably pushing my luck to have a go at rebuilding these things, but by the sounds of it they have an air leak or some kind of busted seal. 
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: TranceMachineVienna on Dec 06, 2018, 10:11:50
Very nice Sir!Iīll be crackinīa cold one and watching!
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Maritime on Dec 06, 2018, 10:30:56
Any idea what brand they are Mike?  Probably pushing my luck to have a go at rebuilding these things, but by the sounds of it they have an air leak or some kind of busted seal. 
They're OEM Honda, prob made by Koni.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: teazer on Dec 06, 2018, 11:15:08
I think that Honda OEM shocks were made by SHOWA.  If those are FVQ type they were known as fade very quickly and are not very useful on a bike.  OK as boat anchors I'm told
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Dec 06, 2018, 11:35:33
Seems they're rare as hen's teeth, certainly as far as google image search is concerned - did find one image but it was in Czech, lead nowhere (item had sold I think) and, well, my Czech is significantly compromised by the fact that, as a language, I speak it not at all.

Think I'll be consigning these to the big pile of crap building steadily in the corner of my garage.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Sonreir on Dec 06, 2018, 12:08:31
I had a set (told they were from a CB650) on my 360 for a while. I didn't care for them, but I think that may have been because they were just a poor match for the bike.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Dec 06, 2018, 12:57:27
I have Progressive shocks on my other 750 and theyíre a huge improvement on the cheapo Emgo shocks I bought originally. They didnít come cheap but hey, get what you pay for.

Unless I can dig up another manufacturer for a better price, Progressive will probably be welcoming another bundle of my hard-earned soon enough.


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Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Maritime on Dec 06, 2018, 13:05:55
I think that Honda OEM shocks were made by SHOWA.  If those are FVQ type they were known as fade very quickly and are not very useful on a bike.  OK as boat anchors I'm told


You're prob right and looking again they aren't the same as mine, the ones Jussy sent me were from and F and they have preload, rebound and compression adjustments on them.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Maritime on Dec 06, 2018, 13:06:47
I have Progressive shocks on my other 750 and theyíre a huge improvement on the cheapo Emgo shocks I bought originally. They didnít come cheap but hey, get what you pay for.

Unless I can dig up another manufacturer for a better price, Progressive will probably be welcoming another bundle of my hard-earned soon enough.


Sent from my iPhone using DO THE TON

Check out Hagons as well, spendy but great reviews. They're on my when I can afford them for the GL list.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Dec 09, 2018, 11:33:05
Yesterday was a day.  It was a cold one at that, 5F.  That's firmly in witch's tit territory.

Once I'd basically Mother Hen'd the shop heater and regained some feeling in my extremities it was time to start the tear down.  It went pretty well, and a few hours later I was looking at this -

(https://i.imgur.com/2YQP4ce.jpg)
(https://i.imgur.com/zNjDagG.jpg)

Nothing too catastrophic, couple of seized bolts here and there and some iffy wiring to the rear end but otherwise - so far - in pretty good knick.  Two words to any novice like me reading this - Ratcheting Wrenches.  What a tool.  Picked up a set when they were on sale a few months back and I'll never look back.  In true bait-and-switch corporate fuckery the set didn't include 12mm and 14mm (each cost about the same as the entire set) but whatever.  That's Santa's business this year.

Oh.  Resto-mod?  Resto-mod my ass.  Don't know who I was trying to kid.  As soon as I started eyeing up the rear subframe, teeing up where I'd be chopping it off, I knew this bike belongs in a different forum.  Not sure which yet, but sure as shit not here.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: teazer on Dec 09, 2018, 12:27:00
Intriguing.  What are your thoughts about the new vision?  Chopper, hardtail, cafe, "brat" stock?
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Sonreir on Dec 09, 2018, 16:24:32
Love the feeling of having a roller. Nice work.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: esmoojee on Dec 09, 2018, 18:56:24
Hereís a cheaper shock option for you....  http://chrislivengood.net/wp/product/honda-cb-rfy-kit/
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Dec 09, 2018, 21:38:20
Hereís a cheaper shock option for you....  http://chrislivengood.net/wp/product/honda-cb-rfy-kit/

Thanks for the link mate, I've come across those RFY shocks before.  These are rebuilt and modded?  Interesting - always liked the look of piggyback shocks but either a. couldn't afford Ohlins or b. wasn't sure how good the Chinese versions were.  Not sure how good these ones are, but they sure look the part.
Title: Re: 1982 CB750F Resto-mod. At least that's the current plan.
Post by: Jimbonaut on Dec 09, 2018, 21:49:08
Thanks in no small part to the advice I got with my last CB build, getting the motor out this time was a breeze.  Mobius recommended keeping both wheels on to allow for easier tip-over-ability so that's what I did, but not before loosening up (fork, engine mount nuts, swing arm nut) or removing (rear shock, frame section) everything on the right hand side of the bike.  That way, when the things lying on its side, you haven't got a bunch of crap getting in the way from lifting the frame off the engine -

(https://i.imgur.com/o1bOy3z.jpg)

I also removed the front sprocket and unhooked the chain from it - that way I can pull the rear wheel and swing arm off the bike once it's lying on its side.  Less weight when it comes to lifting the frame off.  The only engine bolts that I kept in place were these -

(https://i.imgur.com/uyI5B6h.jpg?1)

Tipped her over, removed the swing arm/rear wheel and forks/front wheel and lifted the frame outta there.  Me and a mate hauled the lump onto the workbench and job's a good'un

(https://i.imgur.com/bHbcyek.jpg)

(https://i.imgur.com/qAOYswz.jpg)

At first glance the engine cases all seem to be in good knick, no busted fins, all good.  Moving right along.

Sunday evening.  Here beer here.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 10, 2018, 10:21:06
DOTHETON.com: "Anyone seen that charlatan impersonating a restoration in this forum section?"
My CB: "I'll get my coat".
Title: Re: 1982 CB750F... The resto-not
Post by: teazer on Dec 10, 2018, 11:23:46
Other people in the room " We don't care if he's in the wrong room.  he can stay right where we can find him."   :-)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 11, 2018, 14:33:46
Early days, and still not sure how deep I'm going to go into the engine.  This'll sound messed up but if the compression hadn't been so good (165psi) across all four cylinders then I'd probably seize that as an opportunity to roll my sleeves up and have a crack at an engine disassembly.  Working on the KLR was a great lesson, and its single cylinder was an excellent learning curve - I suppose in truth I'm looking for a reason to get stuck into this inline four.  The cam chain sounds pretty loose in there so maybe that could be my excuse?  Any advice would be very welcome as always.

It would also give me the opportunity to clean up the engine cases, maybe try some vapour blasting as well, and have a go at painting the thing.

It's a long, long winter here in Montreal - time is on my side.

Unless the wife pulls the trigger on the seat sale to Guadeloupe in January ($150 per person?  Rude not to).  Then I may get a week off for good behaviour.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Dec 11, 2018, 14:40:28
If it ain't broke don't fix it.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Dec 11, 2018, 14:46:33
Do the routine maintenance, but don't break it down unless you have to.  No reason to look for trouble.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 11, 2018, 21:31:31
Sound advice.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 12, 2018, 12:14:29
Do the routine maintenance, but don't break it down unless you have to.  No reason to look for trouble.
Irk, if it's not too much to ask, could you give me the bullet points of routine maintenance?  Like a checklist of what to go through?  It would be an invaluable resource for me and a huge help in knowing I wasn't overlooking anything.  Thanks man.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Dec 12, 2018, 12:28:02
Honestly, just oil, plugs, timing, valve lash.  If it runs well, and you have good compression, no smoking, etc.  I wouldn't do much else.  If riding shows your clutch checks out fine, then ride it til is goes.  If the carbs need work, then clean them and replace any rubber.  Otherwise, I'd let them go too, if it's running well.  I'm all about fixing things when broken, but just because it's old doesn't mean it needs fixed.  This DR370 I have is a solid runner.  I'm doing some performance mods, like going to a VM carb, and changing the exhaust.  But I have no intention on cracking open the motor because it's a good runner.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 12, 2018, 12:43:26
Nice one, thanks mate.  This for sure helps, and you guys are right - no sense in fixing stuff that ain't busted. 

Once I pull the valve cover I'll check the valve clearances, and I'll also check the tension on the two cam chains.  Offline, I've been told conflicting things about replacing the valve seals.  On the one hand I've been told replacing the seals is a good idea, but on the other I've been cautioned that replacing the seals will alter the compression in the top half of the engine which would then mean replacing the piston rings as well.  Or something like that (it was all in French - my French is iffy at best).

First off, before doing anything, I'm going to shine a light into the exhaust ports and see if I can see any oil on the valve stems.  If I can't I think I'll leave well enough alone.  If I can I'll probably replace the valve seals.  What's the common consensus on doing this - would I also need to replace the piston rings as well?  Again, with such good compression in the engine I'd rather not.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Dec 12, 2018, 13:00:57
I don't understand how valve seals have anything to do with your compression.  They keep oil from entering the combustion chamber.  They're on the cam side of the motor, not the combustion chamber side.  If they don't leak, keep running them until they do.  With your compression numbers, it appears the valves don't leak either.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Dec 12, 2018, 13:05:25
Nice one, thanks mate.  This for sure helps, and you guys are right - no sense in fixing stuff that ain't busted. 

Once I pull the valve cover I'll check the valve clearances, and I'll also check the tension on the two cam chains.  Offline, I've been told conflicting things about replacing the valve seals.  On the one hand I've been told replacing the seals is a good idea, but on the other I've been cautioned that replacing the seals will alter the compression in the top half of the engine which would then mean replacing the piston rings as well.  Or something like that (it was all in French - my French is iffy at best).

First off, before doing anything, I'm going to shine a light into the exhaust ports and see if I can see any oil on the valve stems.  If I can't I think I'll leave well enough alone.  If I can I'll probably replace the valve seals.  What's the common consensus on doing this - would I also need to replace the piston rings as well?  Again, with such good compression in the engine I'd rather not.

I don't think whoever gave you that advice knows what they're talking about. Bad valve seals, as irk said, only allow oil to enter the combustion chamber resulting in some smoke in the exhaust. They have nothing to do with the rings and can be replaced completely independent of each other.

Honestly, I would just leave the engine alone other than the routine stuff. Get it running and ride it, and fix necessary things as you go.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 12, 2018, 13:09:08
Yeah, now it makes sense.  Of course - I figured something was getting lost in translation.  It's not the first time.  I spent the first two years in Montreal asking for a Russian beer instead of a red one.  French, merde.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Dec 12, 2018, 13:26:23
Yeah, now it makes sense.  Of course - I figured something was getting lost in translation.  It's not the first time.  I spent the first two years in Montreal asking for a Russian beer instead of a red one.  French, merde.

they were probably talking valve "seats" the part the valve seals against in the combustion chamber, not "seals" which keeps oil from leaking into the intake or exhaust when running.  with 165 cold compression your valve seats are fine, don't even lap them. And your seals are probably fine too if you don't get smoke on start up or while running.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 12, 2018, 13:32:29
they were probably talking valve "seats" the part the valve seals against in the combustion chamber, not "seals" which keeps oil from leaking into the intake or exhaust when running.  with 165 cold compression your valve seats are fine, don't even lap them. And your seals are probably fine too if you don't get smoke on start up or while running.
Yes!  That was it - valve seats. 

Language barriers + dicky hearing in my left ear = room for misinterpretation.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Dec 12, 2018, 13:42:18
Sooooo, is Russian beer good?
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 12, 2018, 13:54:46
Fan-fucking-tastic.  I think.  Like most beer here - even if I pronounce it all fucked up and order something totally wrong, whatever they bring me is generally excellent.

Unless it's white beer, wheat beer, whatever.  Undeniably and unwaveringly awful, always.  Gose is truly unforgivable too.  Had a few porters last night in a local brew pub.  Damn they're good.  Recently got into porters and milk stouts.  Had a peanut milk stout the other week which sounds weird to say and looks weird to write but tastes amazing.

Russian beer huh.  The world really opens up fast when you have no idea what the hell you're saying in a foreign language.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Dec 12, 2018, 14:17:11
haha I bet it does.  My last drunk was off of oatmeal porter.  Stouts and porters are where i live in the cold months.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Dec 12, 2018, 14:20:52
haha I bet it does.  My last drunk was off of oatmeal porter.  Stouts and porters are where i live in the cold months.

+ 1 here, the porters and high ABV stouts help get through the cold dark months here in Canuckistan
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 15, 2018, 12:41:11
+ 1 here, the porters and high ABV stouts help get through the cold dark months here in Canuckistan
Threw back a few more last night, including a black cherry stout.  Only came in small glasses as they had a limited supply and wanted to share the love.  Another combo out of left field, and another winner.

Thinking about my list for Santa, and eyeing up some Progressive springs for up front.  I have Progressive shocks on the '81 and they're great - anyone got the word on upgrading the fork springs?  The forks on the '82 are air-assisted (unlike the '81), so I guess I'm wondering just how much of a difference I'm going to see in the upgrade.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Dec 15, 2018, 13:39:10
What about emulators?


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Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 15, 2018, 13:50:55
What about emulators?
I had to google them Irk, news to me.  Are they a retro-fit to existing fork set-ups?  Or do they require a complete rebuild (springs etc)?  I'll have to look into them, ta for the insight.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Dec 15, 2018, 15:26:44
. https://youtu.be/j3QYZEQoN_M




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Title: Re: 1982 CB750F... The resto-not
Post by: jpmobius on Dec 15, 2018, 21:21:12
Those things (emulators) really work.  I don't think progressive springs are as beneficial as some think they are.  You buy expensive new parts, put them in, discover a noticeable difference and judge it as an improvement.  Which it may be, but in old forks, the damping is the real trouble and emulators are cheaper.  Many think that straight correct rate springs are the best if the damping is working.  Keep your stock springs until you are certain you need/want them.  First, you can significantly impact the "spring" you have by increasing the fluid volume.  Less air space means that the pressure when the fork is compressed will go up - rapidly if you over do it, so there is a limitation.  Get emulators, then get the sag (distance the fork compresses at rest with the weight of the bike and rider on board) where you want it (start with 1/3 of the travel) by spacing the spring to increase the pre-load.  You can make them from some bits of pvc pipe, so very affordable and you can make a million of them to experiment.  If you want more spring after that, add fork oil. Don't over do it, and measure with utmost accuracy.  If you don't like it after that, figure out what you don't like and change springs accordingly.  Race Tech makes superb pro quality shocks as well, though they are not cheap.  If they are in your budget, you will get what you pay for though.
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Dec 16, 2018, 01:24:08
+1 for a racetech setup. get the most out of your stock suspension. I installed some of their emulators and springs in my kz750 forks. Haven't had a chance to try them out yet, but if they are as good as their shocks I think they will be a nice upgrade.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 16, 2018, 10:49:49
Great info.  I'd never heard of these things but having emulators as an option is very good to know.  I checked them out on the race tech site - $180.  That's considerably more expensive than a set of Progressive springs ($90) but clearly the emulators have clear advantages.  Not sure how good I've been this year - think Santa might bust a nut if I put these things on my list.

Pulled the valve cover and checked the valve clearances -

(https://i.imgur.com/QrJKd6I.jpg)

- I'll refer back to my other CB thread for comparison but judging by Clymers these are all within spec, right?  If any need switching I have the tool to lift the cams.  I also checked both cam chains and their tension.  The intake cam chain was nice and tight, and this time thankfully the tensioner bolt had not stripped the threads in the engine housing unlike my other CB.  There's a fair amount of oil on the front of the engine - I noticed that the small o ring that sits underneath the tensioner bolt's nut was a little buggered, so maybe a new o ring in there will snug that up.  The intake chain was loose as hell - loosened and then tighten the two acorn nuts on the rear of the engine and tightened that thing right up.  I was pretty surprise actually how much slack was in the chain before, and how tight it got after making the adjustment.

(https://i.imgur.com/NdUfhIL.jpg)

Was reminded of one snafu, and that's #4 spark plug.  It's been cross-threaded at some point in the murky past, and now sticks out at a jaunty angle and only threads in about half way into the head -

(https://i.imgur.com/VovF1q4.jpg)

What would be my options for re-tapping the threads?  Pull the head?  Or can I helicoil/timesert the thread with the head in place? 

Slung the wheels back on the frame and got the bike up against the wall for a mug shot -

(https://i.imgur.com/iUstvu9.jpg)

This is going to help work out the lines and seat design. I'll fire up the grinder soon and tidy up the frame, always the fun part.
Title: Re: 1982 CB750F... The resto-not
Post by: farmer92 on Dec 16, 2018, 11:33:12
Great info.  I'd never heard of these things but having emulators as an option is very good to know.  I checked them out on the race tech site - $180.  That's considerably more expensive than a set of Progressive springs ($90) but clearly the emulators have clear advantages.  Not sure how good I've been this year - think Santa might bust a nut if I put these things on my list.


The emulators will help with the damping, which in my humble opinion is of far greater importance than spring rates.

I would almost argue that you could play with the oil level in the forks and achieve a nice progressive rate without changing out the springs.
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Dec 16, 2018, 17:16:52
auto shops heliocoil spark plugs holes everyday and don't break the engines down. a couple small aluminum chips wont hurt your engine, but don't drop the helicoil tang down there.


https://www.popularmechanics.com/cars/how-to/a1350/4212608/
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Dec 16, 2018, 17:23:30
+1.  I've helicoiled a plug or two, unfortunately.   Fortunately, those bikes were bought dirt cheap for such an easy fix.  Many, if not all, auto parts stores sell helicoil kits specifically for spark plugs.  Everything together in a pre-packaged kit.
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Dec 16, 2018, 21:45:54
The 750 site folks advocate looser valves - .004 to .005and avoiding .002 even though it is in Honda spec. Particularly the exhaust valves are prone to burning if too tight appearantly. On the front adjuster lock - once you put a new o-ring on it, only tighten it and the lock nut with two fingers on the wrench. Very easy to strip (as you've found) or break (as mine was).
Title: Re: 1982 CB750F... The resto-not
Post by: ex119x on Dec 17, 2018, 02:57:55
.002 is just a little too tight for me on those motors. I like the exhausts at a loose .003 - loose.004. As far as the forks go, if you don't want to spend the money on emulators and straight weight springs, then I think Progressive Suspension springs and slightly heavier oil, 20 wt, is an OK way to go. On street bikes I feel like the progressive springs and good oil do a pretty good job. On the race track I prefer emulators and straight weight springs, although I have both set-ups in the garage at the moment.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 17, 2018, 11:24:56
Excellent info - I'll look into the emulators further for sure.  I like the idea of having a fully tuneable system in the forks - especially given Montreal's highly questionable road surfaces.  My shoulders aren't what they used to be - whatever I can do to absorb our bombed-out roads the better.  I'll do some more homework on the Progressive springs too - it seems like both options have their merits.  The bike will definitely be taken out for some pretty spirited riding but nothing too crazy - just want to make it as comfortable as possible.

I'll also go the helicoil route, and probably with the head in place.  Helicoil over TimeSert?  I used a TimeSert on the last CB (for a stripped tensioner bolt thread).  Take my time, do it right the first time.

There's a guy not far from me who's my go-to for parts and general knowledge on all things moto - he also as a bag of shims which he lets me swap out if I need any.  I'll loosen up the exhaust valves by a few 000's - think I should loosen up the intakes as well?  Anything I can do to get the old girl breathing better.

Chopped off the rear subframe and de-tabbed the frame -

(https://i.imgur.com/G0Tm6Fy.jpg)

(https://i.imgur.com/nZft9PX.jpg)

I'm going to bend up a new seat hoop, a bit longer than the last CB, so my wife has a slightly better perch.  I really dig the lines on this bike already - need to design a seat that looks the part but is much comfier than the brat seat on Rhonda -

(https://i.imgur.com/gpTPE6D.jpg) 

I love chopping stuff up.  I love that part.  Continued apologies to anyone offended by this bike mis-representing in the Restorations section - I know I know.  It's a charlatan.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 17, 2018, 11:39:38
Also trying to decide if I'm going to keep the centre stand.  I'm kinda loving it even though it's a bit of lump.
Title: Re: 1982 CB750F... The resto-not
Post by: canyoncarver on Dec 17, 2018, 11:40:37
Also trying to decide if I'm going to keep the centre stand.  I'm kinda loving it even though it's a bit of lump.

Heavy and ugly but man they are handy.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 17, 2018, 11:48:10
Heavy and ugly.  And that's being polite!

Otherwise I might muck about with the rear axle somehow, extend it so that I can hoik up the rear end on one of those snazzy race bike rear wheel lifts.  They always make you look like you know what the hell you're doing.
Title: Re: 1982 CB750F... The resto-not
Post by: wozza on Dec 17, 2018, 18:12:36
Heavy and ugly.  And that's being polite!

Otherwise I might muck about with the rear axle somehow, extend it so that I can hoik up the rear end on one of those snazzy race bike rear wheel lifts.  They always make you look like you know what the hell you're doing.
Dont do that :) ....the main use for the paddock stand is to remove the rear wheel :) weld some tabs to the swing arm and get some stand off's....Or remove the spring ect for the stock center stand so its easy to remove after use
Title: Re: 1982 CB750F... The resto-not
Post by: teazer on Dec 17, 2018, 18:29:10
Or get some longer bolts for the shock lower mount and fit spools on those. Easy peasie
Title: Re: 1982 CB750F... The resto-not
Post by: 1fasgsxr on Dec 17, 2018, 18:45:33
+1 ^^ What teazer said.^^  that's what I did
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Dec 17, 2018, 21:51:56
+1 ^^ What teazer said.^^  that's what I did
Me too.... on a GoldWing! Still works well.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 18, 2018, 10:40:06
Dig this idea a lot.  I'll see if I can get something like these spinner spools with a long stem -

(https://i.imgur.com/LLG4txV.jpg)

- and bolt them into the lower shock mount.  I'm all over that like a hobo on a ham sandwich. 
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 18, 2018, 19:52:56
Started cleaning up all the oil, grease, muck and shite off the lump -

(https://i.imgur.com/Rwo1beT.jpg)

- thankfully it's not as bad as Rhonda's.  No beauty either, but in better knick.  After dicking about for 5 minutes with a toothbrush between the fins I figured there had to be a better way.  Better way = bigger brush...the chain brush worked like a champ.  It's a bit...flicky.  Be prepared to wear plenty of crap, and don't be surprised if you're flooded with compliments on your new freckles.
Title: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 18, 2018, 19:54:35
Also discovered that at least one of the valve cover bolts has stripped the threads in the head. Time for more TimeSert shopping?
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Dec 18, 2018, 22:00:29
Also discovered that at least one of the valve cover bolts has stripped the threads in the head.  Time for more TimeSert shopping?
I found that a PO had not only replaced some valve cover bolts with regular (and, wrong-threaded) bolts, they cracked one of the cam holders - I suspect by forcing in the wrong bolt.

BTW, this is what I did to use a pit stand on the GoldWing. The stand is a Harbor Freight, the adapter from Amazon, and the spools made out of aluminum slugs that came in RF line sections in place of decouplers. I had to order Grade 12 Allen bolts to get them long enough.
    (https://uploads.tapatalk-cdn.com/20181219/18ecbe5f6d8830ab57ea34abbd6c81e1.jpg)
(https://uploads.tapatalk-cdn.com/20181219/e1482c7a09bcbc6e04c22debac81b0f0.jpg)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 19, 2018, 00:52:36
That looks sharp - I like it.  Thanks for the idea - the centre stand Will Be Ditched.

About the stripped cam holder(s) - is this a helicoil/timesert fix or are new cam holders buyable?  Can you replace just one? 
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Dec 19, 2018, 08:01:38
I had to buy a full set from ebay, but only $40, so better than I hoped. He not only stripped it, he split the holder so it must be replaced. Check all of yours to make sure you don't have similar damage. I will go through the ones I receive and pick what fits best (supposed to be line bored, so I'll be checking oil hole alignment as well as plastigauge clearance. Once mine is taken care of, I'd be happy to send you what I don't use.
BTW, I will be replacing "L" cap. I just hope the one coming in is a good fit.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 19, 2018, 11:26:13
That's very generous of you, thanks man I appreciate the offer very much.  The threads looks pretty dicky in most of them, and from what I remember not many of the bolts "bite" when their shoulder snugs up.  I think most - if not all - will need switching out.  I did look on eBay last night but came up short - I'll keep my eyes open.

Plastiguage.  Something I'm familiar with but have never used.  You apply some of the stuff to the surface(s) whose gap you want to measure and then make the measurement by comparing the spread pattern to a chart?  Something like that I think.

Thanks again, I hope the holders you bought do the job.
Title: Re: 1982 CB750F... The resto-not
Post by: teazer on Dec 19, 2018, 12:19:52
Plastiguage is interesting.  It's a thin rod of plastic.  Break off a length and place it on the clean bearing journal and bolt down the cap. Do not allow the shaft to rotate.  Remove the cap and use the guide on the packet to measure the clearance. It comes in different thicknesses, so order a pack that covers the specified clearance. 

Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Dec 19, 2018, 12:55:09
Jimbo, I think that as long as your caps are not cracked Timesert or Helicoil would be your best bet. But be careful drilling for them! You don't have far before the bearing journal. Don't know why these would be overtightened - you just have to compress the rubber seal, and at some point they go metal-to-metal with the flange on the bolt and the cap. I tighten mine on both the GoldWings and the CB750F with a 10mm socket on a screwdriver handle.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Dec 19, 2018, 13:13:44
I don't know why either - seems like an over-zealous PO took out their frustrations on the valve cover at some point.  Steel and aluminium - bad combo if you've eaten too many Weetabix.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 02, 2019, 17:18:47
Happy new year one and all.  Here comes another fucker...let's hope it's a goody.

Ok, still cleaning up the engine.  It's not the most exciting work.  So, until there's more exciting things to document, discuss and report on here are a bunch of photos of the lump in different positions on my workbench.

(https://i.imgur.com/UlThFGn.jpg)

(https://i.imgur.com/1rY0T5A.jpg)

(https://i.imgur.com/2a6aGWb.jpg)

(https://i.imgur.com/su1Aygh.jpg)

(https://i.imgur.com/VMn73xB.jpg)

I like this picture.  The engine looks like its just given up, and face-planted...

(https://i.imgur.com/J09CerK.jpg)

Degreaser, soapy water and a fuckload of brake cleaner.  Ran out of all three so the first Canadian Tire trip of 2019 looms large.  I'm gonna be painting this thing eventually - it's been painted once before.  I hesitate to say badly as I've never painted an engine before.  For all I know it's really really hard to paint an engine and whoever did it did a pretty damn good job.  But it certainly doesn't look great - the paint is peeling in places and there are runs all over the thing.  Any and all input on How To Paint A Motorcycle Engine will be very gratefully received.

Oh, and my Mum gave me the three ratcheting wrenches I was missing for Christmas.  Go the Mums.
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Jan 02, 2019, 18:53:15
On my GL1000 engine I used two different engine cleaners, and one worked muck better (but I don't recall which). I also did a final soap and water bath, rinse, and finished with isopropyl alcohol. I brush painted it with POR-15 engine paint (but then I really dig the MG Maroon color that is available in it). Seems really well adhered and tough.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Jan 02, 2019, 22:08:14
S100.  That's all I'm gonna say. 
Title: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 02, 2019, 22:32:49
Oh shit. Totally forgot I had some of that stuff. I bought some last year and shelved it - is it a good de-greaser as well?


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Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Jan 02, 2019, 22:35:51
Pretty sure it's a de-everything cleaner.  You might have to take a stiff nylon brush to areas where there's a lot of build up, or the dirt/oil barnacles, but it all comes clean. 
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 02, 2019, 22:41:17
 Brilliant, thanks for the reminder


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Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Jan 03, 2019, 09:53:13
I recommend giving everything a final wipe down with acetone before paint. It works great to get any residual grease or oil from your hands, etc off the aluminum.

Also, I typically have a motor broken down and paint the pieces individually, but since you're painting it mostly together I would pop off the left and ride case covers, mask the gasket surfaces off and paint them separately. That way, you don't have covers that you may need to remove one day "painted in" to the cases resulting in cracks and chips when you pull them.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 03, 2019, 09:59:18
That was the plan mate - pull off the side covers (plus the oil filter cover, valve cover, starter motor cover and a few others), mask the thing up and have at it.  The engine's been painted before - do I need to get all that paint off first, or is it enough to rub down the rough spots, knock off the loose stuff, hit everything with primer and then the VHT?
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Jan 03, 2019, 10:10:40
That was the plan mate - pull off the side covers (plus the oil filter cover, valve cover, starter motor cover and a few others), mask the thing up and have at it.  The engine's been painted before - do I need to get all that paint off first, or is it enough to rub down the rough spots, knock off the loose stuff, hit everything with primer and then the VHT?

I'd get all the flaking crap off and see what it looks like. If you have chipped spots they will need to be sanded down and blended or you'll see them in the paint. You'd probably only notice it in the flatter areas like side covers, the top of the cases etc. If its really bad you may want to remove all the paint with aircraft stripper or other paint stripper, just be sure its safe for aluminum.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 03, 2019, 10:19:46
Yeah, I was afraid you may say that!  There are a few spots where the paint job is pretty rough so I may attack those with stripper, but thankfully they're in fairly easily reached areas.  The thought of stripping off all the paint though, that sounds like a nightmare.  I'll get the worst off, and chalk the rest up to experience...
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Jan 03, 2019, 18:51:55
i had to deal with a spray bomb once. Get some expanding rubber plugs in the intake and exhaust ports, refit all your engine cases and go nuts with the stripper. make sure you wear safety glasses when you are using it with a brush cuz it can flick it into your eyes. Ask me how i know....
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 03, 2019, 19:05:34
I found that out the hard way already Doc.  No running water in my garage (or near it)...covered in the stuff I had to make a mad dash outside and bury my arm in the snow up to my shoulder.  Every time I think about it it reminds me of the scene in Raiders of the Lost Ark, when the nazi bugger picks up the red hot medallion and makes a beeline for a snowbank.  My yelps were just as lame as his.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 07, 2019, 19:13:54
Not a million miles off painting this thing now.  Found a rather sculptural position with a fairly solid balance point -

(https://i.imgur.com/2foIfCl.jpg)

- and wondering if that may be a good position to paint it?  I'll probably pull the oil pan off first though and this will probably upset the balance.  If anyone reading has painted one of these lumps before (assembled) and has any pointers re. positions for engine let me know?  I'm thinking two positions - one to get the underside and then roly-poly it to get the rest. 

Is primer the way to go?  This engine has been painted before but without primer.

In other news, I'm going to have to modify the frame brace a little here -

(https://i.imgur.com/BQEt21i.jpg)
(https://i.imgur.com/owsw38c.jpg)

I'm using a K tank on this F frame and so the mounting position is different.  It also doesn't sit flush with the seat frame rails on the horizontal, so in order for it to not get in the way of the seat pan it'll need to be lowered.  However the battery cage also mounts to this so I'll need to be careful with the grinder.  Plan is to cut some slits out and lower it, then re-weld.  In my head it makes sense.



Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 07, 2019, 19:53:00
Clean it  really good and prep it right and you dont need primer but you do need to heat cure either in an oven or by running the engine with duplicolor or vht engine paints. Oh and I should get over this week to get the carb kits and put them on the bus to you.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 07, 2019, 20:46:37
Legend, cheers Mike - carbs are next-ish on the list so that'll be good timing.  No primer?  Sounds good to me.  The selection of VHT paints at Canadian Tire seems to have slimmed down a bit so may end up with a Duplicolor engine enamel instead.  Looks like they're much of a muchness.

When you say prep it right - so far I've de-greased the bejeezus out of it, cleaned it up with S100 and a load of brake cleaner and keyed up the remaining paint/aluminium cases so the paint sticks good and proper.  I still need to wipe the thing down with thinners - is that pretty much it?

Also, will have to cure the paint by running the engine once it's back in the bike - no oven here. 
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 07, 2019, 23:20:51
Yep pretty much that, getting as much oil residue off as possible makes the most difference. I like a wash in full strength simple green, then a good rinse with water as well. Plug the holes.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Jan 08, 2019, 09:11:57
I've always scuffed with 320 grit or similar. And used primer. But since this already has paint on it you'll probably be ok without.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 08, 2019, 09:32:01
I've always scuffed with 320 grit or similar. And used primer. But since this already has paint on it you'll probably be ok without.

I follow the can, I know some don't need primer and some do depending on brand and possibly colour you use.  That being said I always have baked my covers in the oven and then cured the cases with engine heat per cans. I just use a toaster oven in the garage for the covers. I got one cheap at a thift store that can fit a 12" pizza and so can take most engine covers.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Jan 08, 2019, 09:43:40
I follow the can, I know some don't need primer and some do depending on brand and possibly colour you use.  That being said I always have baked my covers in the oven and then cured the cases with engine heat per cans. I just use a toaster oven in the garage for the covers. I got one cheap at a thift store that can fit a 12" pizza and so can take most engine covers.

True. When I did the 360 I cured all the pieces individually in a ghetto oven with a heat gun. On the 350, I painted it completely assembled on an engine stand, and didn't cure it until I had the bike running, which was a few months later. I believe I used Duplicolor on the 350, and it was gas and oil resistant even before I ran it in to cure the paint. I did the same on the RV125.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 08, 2019, 10:07:29
I'll check out what Canadian Tire has in terms of high heat paint and weigh up the options.  Wasn't planning on using an engine stand as, well, I don't have one.  But, thinking about it, my wife bought me a one day welding course for Christmas so maybe I could have a go at making one for my first project.  Would have to make painting the engine a lot easier - presumably with the engine on the stand there's no need to rotate the engine in order to paint it?  Hit the thing all in one go?

I'm not painting the covers, they'll get a different treatment.  I do have a small toaster oven in the garage I picked up for $5 - used it for baking Rhonda's calipers.  I'll cure the engine paint once the engine is running, but yeah I've heard that it's not much cop against oil and gas until it's cured.  Duplicolor is better in that dept?
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Jan 08, 2019, 10:14:41
I'll check out what Canadian Tire has in terms of high heat paint and weigh up the options.  Wasn't planning on using an engine stand as, well, I don't have one.  But, thinking about it, my wife bought me a one day welding course for Christmas so maybe I could have a go at making one for my first project.  Would have to make painting the engine a lot easier - presumably with the engine on the stand there's no need to rotate the engine in order to paint it?  Hit the thing all in one go?

I'm not painting the covers, they'll get a different treatment.  I do have a small toaster oven in the garage I picked up for $5 - used it for baking Rhonda's calipers.  I'll cure the engine paint once the engine is running, but yeah I've heard that it's not much cop against oil and gas until it's cured.  Duplicolor is better in that dept?

Jim, I cant remember but I think I used Duplicolor on the XL and VHT on the Van Van. Neither had a problem holding up to gas or oil. They had off gassed at least 1 month prior to being exposed to any fluids.

I thought I had a pic of the stand I used for the XL. Basically I made some 2x4 bases with a vertical board on either side of the engine. Just ran a threaded rod right through. Kept it about 8-10" off the bench which was just enough to be able to spray the underside.

Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 08, 2019, 10:19:56
That's good to know Nick - as long as they gas off before coming into contact with oil/gas then the paint should be ok?  I'm looking online for plans for an engine stand - may have a go at building one.  Otherwise I'll probably end up painting the engine as it sits on my bench, with a bit of finagling hopefully I won't have to move to around too much.  Damn thing weighs a ton.

If I was to make the frame out of wood, think 2x4's will be strong enough to hold this thing up?
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Jan 08, 2019, 10:27:48
Here is my stand.  I think I paid $30 for it.  Could be made for much cheaper, but I don't mind throwing $30 at my own laziness now and then.

(http://www.dotheton.com/forum/index.php?action=dlattach;topic=76126.0;attach=211049;image)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 08, 2019, 10:31:07
I saw that exact stand Irk on amazon just now.  It's for the SOHC motor though, not sure it'll fit the DOHC and can't find an off-the-shelf version for it.

And damn that's one clean looking engine by the way. 
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Jan 08, 2019, 10:55:44
That's good to know Nick - as long as they gas off before coming into contact with oil/gas then the paint should be ok?

From my experience, I haven't run into any issues. I still think you should avoid getting any gas on the paint until its cured but sometimes floats stick ya know?

2x4 should be fine, just put a brace in between the uprights because they'll want to bend inward with the weight. So you'll basically have an H with a 2x or 1x base on front and back, with a threaded rod or steel rod to hang it. Space the pieces wide enough that you can get the engine in and out.

Alternatively you could hang it from the ceiling of your shop. Lol.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 08, 2019, 11:44:41
Alternatively you could hang it from the ceiling of your shop. Lol.

I would, but I'm worried the chains would interfere with the duct tape that's holding the ceiling together   ;D
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 12, 2019, 18:18:31
Cleaning engines...the enthusiasm is hard to maintain.  Still, it's pretty much a wrap - an indeed that's exactly where it's at now - tucked under a bin bag until I decide what I'm going to do next.  With the mercury plummeting in my garage I pulled out the grinder and chopped off the old seat mounting bracket -

(https://i.imgur.com/cEOHutt.jpg)

- once I've welded in a locknut or something for the tank mount bracket then I think I'm good.  This worked well on Rhonda so I made the same bracket between the frame rails for the seat and fender mount -

(https://i.imgur.com/sdvDP9U.jpg)

- and then called it day.  Colder than a polar bear's toenail today, minus 20 or some shit.  Brrr.
Title: Re: 1982 CB750F... The resto-not
Post by: trek97 on Jan 12, 2019, 19:20:41
minus 20 or some shit.  Brrr.

Your work looks good.  Where you at, up in the north east?
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 12, 2019, 19:24:31
Yeah - up that way and beyond. Montreal...where you canít feel your face for four months of the year, and spend the other eight slowly defrosting. Madness.


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 17, 2019, 09:46:11
Saw a beauty of a Triumph over on BikeExif yesterday with pretty much the exact handlebars I'm looking for.  A guy there pointed me in the direction of Lowbrow Customs where they sell Emgo repro Triumph bars with a "western" bend, but they're out of stock.  Here's what they look like -

(https://i.imgur.com/eym0xZI.jpg)

hmm, they look like...handlebars.  Anyway, they're out of stock - I'm on notification for when they're back in, but anyone know where I can look in the meantime?  Found a few sets in the UK that'll cost me my shirt in shipping, but not a lot on eBay otherwise.  Of if anyone knows of something similar that could absolutely work too.   
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 17, 2019, 09:53:48
just did a search on a few sites, they are "sold out" on any that carry them. Do any of the UK sites have the measurements? Bikemaster may make the same bend called something different and you can search by width, height, pullback etc.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 17, 2019, 09:55:30
Yeah Mike, that's where I'm at too.  Not in a huge hurry, so hopefully Lowbrow will get them back soon. 
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Jan 17, 2019, 09:58:19
Yeah Mike, that's where I'm at too.  Not in a huge hurry, so hopefully Lowbrow will get them back soon.
You're looking for Flanders handlebars.  Much better quality bars than the EMGO and the bars EMGO is copying anyway.

http://www.sideroadcycles.com/ImportedMotorcycles/ImportHandlebars/ImportHandlebars78.html
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 17, 2019, 10:05:10
Thanks for the link Irk - just had a look but will need a more thorough dig to see if they have the bar I want.  They may be a little out of my budget too, damn.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 17, 2019, 10:21:15
I've run Emgo on 4 bikes and all were just fine. I have them on the GL currently. There are better bars out there but I can't afford them.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 17, 2019, 10:21:50
https://www.jpcycles.com/product/zz50250/flanders-7-8-chrome-7-mini-ape-handlebar

These are the same?
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 17, 2019, 10:26:00
Close maybe Mike but no cigar - the triumph repro bars are much wider, around 33"
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 17, 2019, 10:37:20
If you have the widths (overall and center before rise), rise and pull back you can search for bars in 7/8" with the same or very close dimensions and probably find some
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Jan 17, 2019, 10:43:48
You can get them under $100 on Ebay.  That link was just to show you options.

https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=flanders+euro+bars&_sacat=0
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 17, 2019, 10:48:18
You can get them under $100 on Ebay.  That link was just to show you options.

https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=flanders+euro+bars&_sacat=0

Yeah, that's what I was thinking if you can get the dimensions of the "Western" you should be able to find something the same or close enough in another brand
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 17, 2019, 10:49:22
I went to Emgo's site but they don't list the Western in their newest catalog so it might be discontinued or labeled different now
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 24, 2019, 11:18:58
Got word the bars were back in stock, shnaffled some up in double-quick time.  Been thinking about colour schemes for the engine too, as the PO painted it black I'm thinking a semi-gloss black, exposed fins with bare, polished side covers.  Bit of a swerve as I was never crazy about black engines, but seeing it just now on the new Street Twin may have just changed all that.

Progress slow as molasses in, well, January.  Cut into the frame to make space to weld in a nut for anchoring the K tank I'll be using - hoping to get the frame cleaned up, hoop bent and welded and get it to paint in the not-too distant. Just need to defrost my eyeballs first. 
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Jan 24, 2019, 11:42:51
I've found that Amazon is a good place to search for bars and compare them. Have had good pricing there, too. The bars that I put on my '79 CB750F (Bikemaster 7/8" GP Touring bar) are the same as the ones I put on my '78 GL1000 (Bikemaster 7/8" European bars), except about 2" narrower and black. Honestly, narrower is so I can take the bike to the other side of the basement without taking it outside and back in like I have to do with the GL1000.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 24, 2019, 13:18:16
Semi gloss black with polished fins and covers is a nice combo. I've done it on 2 engines, Parallel twin and a V-4, the v4 was water cooled but had fake fins to look air cooled. (Honda Magna) easy part on that was the fins came off LOL. Made painting, sanding edges and polishing them way easier.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 24, 2019, 13:59:45
Semi gloss black with polished fins and covers is a nice combo. I've done it on 2 engines, Parallel twin and a V-4, the v4 was water cooled but had fake fins to look air cooled. (Honda Magna) easy part on that was the fins came off LOL. Made painting, sanding edges and polishing them way easier.
Nice, you got any photos/links Mike?
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 24, 2019, 14:03:26
Nice, you got any photos/links Mike?

Let me look, I did a thread here but can't remember what I took pics of. One thing I did do that made it better was to flatten/square off the ends of the fins with a belt sander to make it easy to mask them with tape and a razor blade.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 24, 2019, 14:05:41
http://www.dotheton.com/forum/index.php?topic=63677.0

link to the magna
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Jan 24, 2019, 14:18:02
I tried doing the polished fins thing on the 360. I painted the whole head black and then tried to file it off after the fact. The paint chipped and I had to repaint. So I can recommend NOT doing it that way LOL.
 
Sanding them flat first and taping them up sounds like a better plan.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 24, 2019, 14:21:17
Nice, I've seen that build thread before Mike.  Quite the looker, great job.  Damn, that looks like a ton of work masking off the fins, more so as I'll be painting the engine in one big lump.  I was planning on painting the engine and then sanding back the fins after.  But the polished fins on your Magna look sweet, and I guess polishing them/masking them before paint is the only way to get that look. 
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 24, 2019, 14:22:05
I tried doing the polished fins thing on the 360. I painted the whole head black and then tried to file it off after the fact. The paint chipped and I had to repaint. So I can recommend NOT doing it that way LOL.
 
Sanding them flat first and taping them up sounds like a better plan.
That answers my question perfectly!
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 24, 2019, 14:26:52
The masking isnt that tedious if you flat the first. Tape, slice at 90 deg with razor, done. Peel off after paint and let it cure then rub with polish.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 24, 2019, 14:28:00
A few passes with a belt sander then a few rubs with finer paper is enough. A file for areas a bet wont reach
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 24, 2019, 14:29:27
The masking isnt that tedious if you flat the first. Tape, slice at 90 deg with razor, done. Peel off after paint and let it cure then rub with polish.
A few passes with a belt sander then a few rubs with finer paper is enough. A file for areas a bet wont reach
Nice, great info
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Jan 27, 2019, 05:47:10
I sand fin edges back first to the level of polish that is desired. then paint the whole thing without any masking. once he paint has dried take a rag with acetone and carefully wipe the fin edges off. Since they are already polished its comes off very easy and gives a nice crisp line with zero chipping. it lets you do the internal fins if you want without risk of damaging the fresh paint.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 27, 2019, 10:15:02
Cheers Doc - think your method would also work if I don t heat cycle the engine first before acetoning the fins?  Iíll be painting the engine soon but itíll be a while before rebuilding the bike and reinstalling the engine. I donít have an oven and the engine is gonna be painted assembled.


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 27, 2019, 23:29:03
Had a go at filing down the fins.  Turns out it's a really satisfying little job.  Here's a during -

(https://i.imgur.com/Vgm39Ff.jpg)

and here's job done -

(https://i.imgur.com/DZeOZDA.jpg)

Feeling it.  Definitely feeling it. They still need a finer sand and then a polish - undecided if I'll go the Maritime tape-and-paint route or the Doc Rot polish-and-acetone plan but both sound groovy  8)
Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Jan 27, 2019, 23:51:04
That looks nice.  Did you file parallel to the fins, I think that would be less likely to cause chipping?
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 28, 2019, 10:59:40
That looks nice.  Did you file parallel to the fins, I think that would be less likely to cause chipping?
I haven't painted the engine yet (it was painted black by the PO) but when I filed  yeah it was pretty much at right angles to the fin.  Not so much on the front and back of the engine (where the fins are tapered), but - on this old paint at least - no chipping.

Either I'll tape and paint or polish, paint and acetone.

Hopefully later this week my man Kieran's gonna help me bend up a hoop, weld the thing up and then I can get the frame painted.  Saturday was de-shit the frame and swing-arm day so it's pretty much ready for its close up.  Also doing a welding course this weekend, so, yeah - fabricating.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 28, 2019, 11:17:37
Either works, I found the acetone way a little more messy. used it on logos that were harder to mask off. Either works. Looks pretty good.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Jan 28, 2019, 11:27:44
If it's messy, than you may not be doing it right.  You just fold a rag (I use and old t-shirt) into a 4" x 4" square, then soak one side in acetone and clean the paint off.  You have to flip to clean sides of the rag when one side gets full of paint. It's not messy at all.  Using the folded rag allows you to span several fins at once..
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 28, 2019, 11:31:07
It wipes right off the polished fin edges? Without wiping off any of the paint on the fins themselves? What if the engine/paint hasnít been heat cycled - will the paint have cured enough not to get wiped off by the acetone (apart from the polished edges of course)?


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Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jan 28, 2019, 11:46:36
If it's messy, than you may not be doing it right.  You just fold a rag (I use and old t-shirt) into a 4" x 4" square, then soak one side in acetone and clean the paint off.  You have to flip to clean sides of the rag when one side gets full of paint. It's not messy at all.  Using the folded rag allows you to span several fins at once..

On fins I see this being the case, on little tiny badges I could barely hold I got some paint on me LOL. Jim you need to wipe off as soon as the paint is dry, before cured
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Jan 28, 2019, 11:48:29
TBH, I have no idea about heat cycled paint, since I've never done it with cured engine enamel.  As far as what it gets off, it depends on what you use.  I use tightly folded cotton cloth, so it's kind of stiff.  I soak one side, but I don't go nuts.  Basically, you want it damp with acetone.  Then just rub the paint off.  If the cloth is folded tight enough, it won't touch the sides.  I've also done this on my BMW's Lesters.  I just painted the entire rim, then rubbed the outer lip clean with the rag and acetone.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 28, 2019, 11:54:23
^^ gotcha
Title: Re: 1982 CB750F... The resto-not
Post by: jordandogtown on Jan 28, 2019, 11:55:19
The test looks great, Jim. I'm planning to do the same so a lot of good info here.
Title: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 28, 2019, 12:07:32
A bike mechanic friend of mine came round the garage yesterday and we go to talking about my plans for the engine.  Truth be told I'm a bit polarized about what do to, what with the engine having such good compression (165psi across all four).  Common sense would suggest leaving well enough alone - if it ain't broke don't fix it kind of thing.  However there are a couple of motivating situations that would make pulling the head make sense.  I'm totally 50/50 on what to do, but figure there's no wrong decision really.  Here's the skinny -

Vote for pulling the head -

- have a stripped spark plug thread, helicoiling that mofo would be much easier plus no danger of shit falling into the cylinder
- I could change the valve seals.  As far as I could tell before the tear-down the bike's not smoking, and I can't see any oil on the valve stems when I look into the exhaust ports.  But if they haven't been changed in 35 years then now could be a good time to do it
- would make painting the engine easier
- I'm in no huge hurry to get the bike finished
- need a gasket kit anyway ($90) which has the seals included
- learn new skills. Because, skills

Vote against -

- compression's excellent, why go looking for problems
- see above
- see above

Maybe this isn't the engine to learn on - but if it starts smoking a few months down the line because the valve seals are cracked then maybe it was. 

Pondering with intent.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 28, 2019, 12:09:24
The test looks great, Jim. I'm planning to do the same so a lot of good info here.
Right on - once I've painted the lump and attacked the fins one way or another I'll post up pics of the finished article
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Jan 28, 2019, 22:21:37
The engine is already out. I vote to pull the head (but then, I'm not the one doing it). Certainly would make the Timecert work easier.
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Jan 29, 2019, 14:26:00
It wipes right off the polished fin edges? Without wiping off any of the paint on the fins themselves? What if the engine/paint hasnít been heat cycled - will the paint have cured enough not to get wiped off by the acetone (apart from the polished edges of course)?


Sent from my iPhone using DO THE TON

yes wipes right off, just do as Irk described not use to much acetone, and keep the rag flat. i would do it before it cures.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 31, 2019, 18:19:15
Chatting with a moto guy today, told me in order to repair the crooked spark plug thread I have to pull the head, no matter what.  Folk here have said that this is a job that can be done - carefully - without pulling the head.  The thread is totally crooked, easily 10-20 degrees off true.  Helicoil is the way to go I'm told, bit what gives?  If I drill out the new hole for the helicoil very slowly, and with the bit covered in grease, that should do it, no?  Obviously I want to avoid shit from falling ito the cylinder, but I've never installed a helicoil before so trying to get the skinny on how to approach the job.

Again, to pull the head or to not pull the head - that is the question.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jan 31, 2019, 18:24:50
Also scored a free monster vice -

(https://i.imgur.com/ywEOMM2.jpg)

I think it's about 2000 years old and weighs as much as my car.  Seems legit. 
Title: Re: 1982 CB750F... The resto-not
Post by: 1fasgsxr on Jan 31, 2019, 18:28:33
Nice score! I need a new vice...or an old one. Just not my broken one.
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Jan 31, 2019, 20:27:38
Nice vice. I think if your plug is that far off, you might at a minimum consider a Timecert. It's possible that the head may need welded up and redrilled, however.
Title: Re: 1982 CB750F... The resto-not
Post by: jordandogtown on Feb 01, 2019, 09:44:08
I think I would bite the bullet and pull the head. I'm the type that no matter how careful I was with drilling, I'd always be paranoid something slipped by and I would be sitting on a time bomb.

That thinking has also led me to a lot of unnecessary work/frustration, so...
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 01, 2019, 10:36:02
Chatting with a moto guy today, told me in order to repair the crooked spark plug thread I have to pull the head, no matter what.  Folk here have said that this is a job that can be done - carefully - without pulling the head.  The thread is totally crooked, easily 10-20 degrees off true.  Helicoil is the way to go I'm told, bit what gives?  If I drill out the new hole for the helicoil very slowly, and with the bit covered in grease, that should do it, no?  Obviously I want to avoid shit from falling ito the cylinder, but I've never installed a helicoil before so trying to get the skinny on how to approach the job.

Again, to pull the head or to not pull the head - that is the question.

If its me I'm not gonna risk it for the biscuit, I'd pull the head.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 01, 2019, 10:43:09
Not gonna risk it for the biscuit.  Shit man, I'm stealing that.

Pull the thing?  Think that's the best option?  Weighing everything up it makes sense on many levels.  I'm listening to some righteous dub, makes any decision easier.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 01, 2019, 11:11:05
Not gonna risk it for the biscuit.  Shit man, I'm stealing that.

Pull the thing?  Think that's the best option?  Weighing everything up it makes sense on many levels.  I'm listening to some righteous dub, makes any decision easier.

Its not a whole lot of extra work, and not much to mess up. While its out you can do the valve stem seals, and do the alcohol test to make sure your valves are all sealing properly.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 01, 2019, 11:22:06
Its not a whole lot of extra work, and not much to mess up. While its out you can do the valve stem seals, and do the alcohol test to make sure your valves are all sealing properly.
That's the plan - once I pull it then I can do the valve seals as well, maybe do a bit of porting and sort out the spark plug snafu of course.  Not to mention it'll make painting the lump a bit easier. 

Scoping out the best option for a gasket kit, but to be honest I'm not sure exactly what I'll need (other than the obvious).  I know for example there are some copper crush washers that need to go under the cylinder stud nuts but I don't see them in any gasket kit.  This kit for example -

https://www.ebay.com/itm/Engine-Rebuild-Kit-Honda-CB750-C-F-K-L-SC-1979-1982-DOHC-Gasket-Set-Seals/173035071895?fits=Year%3A1982%7CMake%3AHonda&hash=item2849b1a997:g:pX4AAOSwdTJaa7w9:rk:1:pf:1

- seems complete but not sure if there's anything else I need to order.  Any ideas?
Title: Re: 1982 CB750F... The resto-not
Post by: jordandogtown on Feb 01, 2019, 11:37:05
Can't help with the gasket kit - but you might as well throw in a big bore kit while you're in there?  ;D
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 01, 2019, 12:35:35
Can't help with the gasket kit - but you might as well throw in a big bore kit while you're in there?  ;D
My man  8)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 04, 2019, 10:33:23
Built a workbench yesterday for the bench grinder and vice I scored last week -

(https://i.imgur.com/Ephn6eg.jpg)


Ye gads that vice is h-e-a-v-y, but the workbench is a stout little bugger so all should be well.   My garage is starting to look like a workshop now.  I feel...promoted.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Feb 04, 2019, 10:44:33
Nice, I need the grinder/polisher for my shop. Have the vice on a rolling tool box and wouldn't give it up for anything. Super handy.  You'll find you use that vice all the blessed time.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 04, 2019, 11:10:44
Picked up the grinder from kijiji for $30 CAD - result. 

My wife got me a welding course for Christmas which happened on Saturday, loved it.  Learned about MIG welding and got to grips with the basics, even managed some half-way decent welds by the end of the day.  I didn't realize that the steel that you're welding actually melts and fuses with the wire - now I understand why a decent weld is so strong.  Now just need to find me a useable welder and I'm off to the races. 
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Feb 04, 2019, 11:20:19
Nice, that's something I'd like to do soon as well. My wifes uncle is a pro welder, been doing it for a living for 50+ years, he's still working in his late 70's because he's a fabricator, not just a welder and he has customers who don't trust anyone else.  He told me he'd show me some Mig someday, I need to take him up on that offer before he's not able too.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 04, 2019, 11:25:53
For sure man, you should.  It's really, really satisfying - very visceral and, well, who doesn't love a ton of sparks.  Cleaning the welds up is cool too - I need to get me a welder.
Title: Re: 1982 CB750F... The resto-not
Post by: trek97 on Feb 04, 2019, 20:00:37
Also scored a free monster vice -

I think it's about 2000 years old and weighs as much as my car.  Seems legit.

OH hells to the yes.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 09, 2019, 23:04:49
Was going to clean up a few frame parts, get them ready for paint, but when I got to the garage all my cleaning products were frozen solid.  So this happened instead -

(https://i.imgur.com/CykkDLf.jpg?1)

The "ahh, fuck it" argument won the day.

Got the timing marks all in the right place before I dove in, but buggered if I could get the exhaust cam drive chain off its sprocket without moving the cam.  I understand the principals now of the timing chain/cams/valves but a bit misty on how important it is to keep the timing mark in the same position throughout the procedure.  Very misty truth be told. 

Also, the base gasket separated a mm from the crankcase - does this mean I have to pull the cylinders and replace the gasket?  It's not torn or anything.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 10, 2019, 12:35:02
For documentation purposes - and so that perhaps more proficient mechanics can offer any insight - here are the steps I took

1. Got the timing marks lined up (on this CB it's the "T 1 4" you're looking for) -
(https://i.imgur.com/l2fjk9q.jpg)

2. Removed the cam chain and tensioner guides -
(https://i.imgur.com/Qub0SP6.jpg)

3. Removed the cam holders in the correct sequence, the cam sprockets and the cams -
(https://i.imgur.com/SG1pQHR.jpg)

4. Removed the valve shims and buckets, bagged and labelled them

5. Removed a few bolts, tapped around the jugs with a rubber mallet and lifted the cylinders off the crankcase -
(https://i.imgur.com/Z2hnwRF.jpg)

Head/valves -
(https://i.imgur.com/Xakq6VF.jpg)

One of the guide dowels is stuck in the cylinder case, the other one stuck in the head.  PB blasted them and will see what gives. 
Title: Re: 1982 CB750F... The resto-not
Post by: trek97 on Feb 10, 2019, 18:38:46
Looking good dude.  Keep track of them dang insulators, both, where they go and orientation.
Title: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 10, 2019, 21:28:27
Insulators?  What be they - another name for the cam guides?
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Feb 10, 2019, 23:25:50
Insulators?  What be they - another name for the cam guides?
What most people call the carb boots are actually called insulators.  They're numbered, so you don't have to worry about mixing them up, and they're a different size for the head side and the carb side.
Title: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 10, 2019, 23:50:35
Ah, those things. Iíve been calling them jug boots. Yeah, I need to get those things off, but itís so damn cold in my garage theyíre rock solid. Need to - ahem - borrow the wifeís hair dryer and soften them up a bit.

Fuck itís cold here. ďHow cold is it?Ē  So cold I saw a cop tazering himself to keep warm.


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Feb 11, 2019, 00:13:42
I would replace the base gasket otherwise you probably will be tearing it down later to replace it anyway. Doesn't matter about the timing marks, you will have to re-time the cams upon assembly. I would also consider measuring the cylinder bores to see if they're out of spec and if that checked out I personally would do a flex hone and maybe new rings. Just takes one cheapy engine rebuild to make you do it twice, but to each their own
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Feb 11, 2019, 07:21:57
If you post about the boots on an F site, you will be corrected. They say it is because their search engine won't find it unless you use insulator. I've used a heat gun to soften the boots both for installation and removal of the carbs. And that is in a heated garage. It helps to keep from cracking the old rubber. I also smear a light bit of silicone vacuum grease on them to install, but that may not be necessary. At least the last time I didn't have to used a ratchet strap to assist installing them. Maybe third time is the charm, 'cause they finally are all four working and not leaking. Hint: hook up throttle cables BEFORE putting the carbs on the insulators. I prop the at ~45 degree angle part-way behind the head to hook them up, the lower them in position and commence heating the insulators.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 11, 2019, 09:14:36
There ya go Jim. Looks like you've got a couple burnt up looking exhaust valves so wouldn't hurt to make sure they are all still sealing up (alcohol in the ports test) and you'll definitely want to check your valve clearances and probably loosen those particular exhaust valves up a bit.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 11, 2019, 10:45:42
Thanks chaps so that's what a burnt valve looks like.  Knew pulling the head was going to school me.  Pretty sure I did the alcohol test with the KLR but will need a revise on the process - essentially I'm looking to see how tightly the valves seal by pouring alcohol into the ports, correct?  Both intake and exhaust?

Doc, good advice.  I wasn't really planning on doing a complete top-end rebuild, largely because it seems (to amateur me at least) largely unnecessary.  The compression is was excellent (hopefully will be again once I put everything back together again) and so I didn't plan on going any deeper than necessary.  That said, I was looking at the jugs yesterday thinking, well, I've got this far...

Pulled all the side covers, oil pan and whatever else I could off the crankcase - not long before it's ready to paint.  Thanks for the info on the timing - it's starting to make more sense now.  I can't get my head around the importance of the timing mark before pulling the cams, but I totally get the importance of getting that mark in the right place before putting them back.

That happened yesterday, but not before the first decent skate of the year.  When you live in the deep freeze, you take the perks where you can get 'em.

(https://i.imgur.com/u5wPKBQ.jpg)

Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 11, 2019, 11:09:44
Man, its been years since I've skated. We used to have a blast playing pond hockey when we were younger.

To check the valves, pour alcohol (not beer  ;D) into the intakes, give it a good 20 minutes or an hour or so and check for any leaks. Take note, empty and dry them out and repeat on the other side.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Feb 11, 2019, 11:10:27
Just because they're light, or appear a little lean, doesn't mean the valves are burnt.  A burnt valve will literally have part of it's edge melted away.  As the pressurized and fuel rich, super heated air is looking for oxygen, it takes the path of least resistance.  Once it finds its weak point, it always pushes through that spot, melting it away.  If you had good compression, then it is unlikely that the valves are burnt, as they would hold little or no compression. 

Also, nothing wrong with just going with a hone and putting it back together.  Depends on how deep down this rabbit hole you want to go.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 11, 2019, 12:56:37
Excellent Nick, I'll do that.  Any excuse to pick up some alcohol.

Just because they're light, or appear a little lean, doesn't mean the valves are burnt.  A burnt valve will literally have part of it's edge melted away.  As the pressurized and fuel rich, super heated air is looking for oxygen, it takes the path of least resistance.  Once it finds its weak point, it always pushes through that spot, melting it away.  If you had good compression, then it is unlikely that the valves are burnt, as they would hold little or no compression. 

Also, nothing wrong with just going with a hone and putting it back together.  Depends on how deep down this rabbit hole you want to go.

How deep indeed.  Call it good and leave the jugs as they are or go full-on Heart Of Darkness on the thing.  Either way, I think you've helped me name the bike - Colonel Kurtz, take a bow.
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Feb 11, 2019, 16:30:42
BTW, that's isoprophy alcohol. The 91% is best, as the 70% "rubbing alcohol" is 30% water so it doesn;t evaporate so fast and lets the alcohol have time to kill germs. You can get 91% at most drug stores and Walmart these days.
Title: Re: 1982 CB750F... The resto-not
Post by: Nybz on Feb 11, 2019, 17:27:26
I think you are on the right track to clean up inside the engine while you got it open.
Compression is good yes, but the peace of mind checking everything out before you put the engine back in the frame is priceless. Plus new skills is great!

Lapping some leaking valves is pretty easy with the right compression tool. Just donít lap too hard as there is a hardened thin layer on the valve face and lapping will get rid of it and the valves life will be shorten dramatically.

Honing (can rent the tool if need) and reringing is pretty straight forward. Maybe not needed and these rings are pretty solid stock.

valve stems....these ones are way better then stock. if you are not on the Cb1100f web forum, check it out.
http://www.cb1100f.net/modules.php?name=Forums&file=viewtopic&t=75877
He also has upgrade cam holder bolts, which are higher grade so they donít break as easy. FYI only 9ft/lb torque on those puppies. Manual says 12 ft/lb or something, you will snap bolts with that.

Cam chains and cam tensioners for sale....not cheap, but better then stock and will last longer then you/your bike.
http://www.cb1100f.net/modules.php?name=Forums&file=viewtopic&t=86245

You can get a full seal kit at a pretty good price. It would require splitting the cases, but who wants a oil leak on a fresh engine? Plus gives you a chance to check your rod and main bearings.

There are four o rings that go on the back (carb side) on the middle studs (at least on my 1979 model) that need to be replaced. Also larger o rings that go around the cylinder in between the base and cylinder.
You can still get the dowel pins, they are sometime just easier to just replace then to try and get them out and damage.

You will want a full engine gasket set and not reuse the base gasket. I use a spray on copper coat for base and head gasket that has worked great on cheap gaskets.

If your insulators are not just frozen and are rock hard from age/heat, they will have a hard time sealing against air leaks. I havent checked them out but there a super cheap aftermarket set on eBay. I opted to get genuine, as they are still available.
The carb-airbox insulators are always cracked and leaking, do your self a favour and get a new set of yours are old. If they arenít cracked now they will be once you start playing with them more.

If you want some better performance, think about replacing your 750 cams with 900 cams. Direct swap.

Looks good! Will be checking on your progress.
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Feb 11, 2019, 20:19:19
And to pull the dowel pins without  damage (except possibly to the dowel pins); find a drill bit that you can just fit the shank into them, put it inside the dowel while you grip them with pliers. This keeps from collapsing the pin and gouging the inside of the case/jugs/head.
Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Feb 12, 2019, 01:07:52
 

Fuck itís cold here. ďHow cold is it?Ē  So cold I saw a cop tazering himself to keep warm.


That"s shocking!
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 12, 2019, 09:47:11
And to pull the dowel pins without  damage (except possibly to the dowel pins); find a drill bit that you can just fit the shank into them, put it inside the dowel while you grip them with pliers. This keeps from collapsing the pin and gouging the inside of the case/jugs/head.

I like this tip. I've always just left those pesky dowel pins in place because I've only ever buggered them up trying to get them out. Good to know.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 12, 2019, 10:17:34
Thanks as always gents for the excellent help and advice.  Isopropyl alcohol - check (think I still have some from when I worked on the KLR).  Lots of great info there Nybz, and many thanks for the CB1100F forum suggestion - I'm signed up now.  Starting to weigh up pulling the cylinder block now, and glad that I cut my teeth with this kind of work on the KLR and its thumper engine.  And pidjones I'm going to try that dowel suggestion, thanks a lot - it's jammed in the cylinder block tighter than a jar of peanut butter at a squirrel convention.  If it does mangle, are they hard to replace?

Edit - apparently not, found the dowels for a few bucks on bikebandit.com -

https://www.bikebandit.com/oem-parts/1982-honda-750-super-sport-cb750f/o/m151786#sch18760

Good to know
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Feb 12, 2019, 10:52:52
Just add those should you need them to the pile O parts I'm building up for you LOL ;D
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 12, 2019, 10:55:20
Just add those should you need them to the pile O parts I'm building up for you LOL ;D
Ha! "We're gonna need a bigger boat greyhound"

They're on the list - $26 US shipped to Canada, $6 shipped within the US.  Shiretown, make some room  8)
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Feb 12, 2019, 11:01:47
Ha, the box your bars came in is like 3 feet long so we can fill that right up LOL.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 12, 2019, 11:09:54
Only 3ft?  Damn, I thought these bars were wider  ;)

Don't suppose those powdercoat samples had arrived had they?  I need to add a petcock and top end gasket kit to the shopping list too - anytime I can return the favour and send a poutine your way mate say the word
Title: Re: 1982 CB750F... The resto-not
Post by: teazer on Feb 12, 2019, 11:13:40
And to pull the dowel pins without  damage (except possibly to the dowel pins); find a drill bit that you can just fit the shank into them, put it inside the dowel while you grip them with pliers. This keeps from collapsing the pin and gouging the inside of the case/jugs/head.

I find that a large EZ out will usually get them out.  Sometimes they need warming a to help break teh grip and in rare cases they need to be dragged out kicking and screaming with a pair of vice grips
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 12, 2019, 12:18:24
I'm taking the head to a mechanic friend this eve who's going to school me in valve spring removal.  We'll attack the dowel at the same time, get that sucker out one way or another.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 12, 2019, 12:32:27
I'm taking the head to a mechanic friend this eve who's going to school me in valve spring removal.  We'll attack the dowel at the same time, get that sucker out one way or another.

Put a socket over the valve spring and whack it with a hammer.  8)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 12, 2019, 13:15:16
"If in doubt, get the hammer out"
Title: Re: 1982 CB750F... The resto-not
Post by: 1fasgsxr on Feb 12, 2019, 13:24:21
Get a magnet and ninja snatch the keepers from the sky...whop pow.. 8)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 12, 2019, 13:37:44
Get a magnet and ninja snatch the keepers from the sky...whop pow.. 8)
NO idea what the hell that means but any sentence that ends with a whop pow deserves attention.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 12, 2019, 13:50:51
NO idea what the hell that means but any sentence that ends with a whop pow deserves attention.

Lol, when you use the hammer method to get the valve spring keepers off, they may or may not go flying across the shop.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Feb 12, 2019, 13:54:19
Ha, the box may be 4' it's long. I didn't go to Maine. Jill did and she forgot to grab the samples. will be back over again soon though.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Feb 12, 2019, 13:58:48
if I were you I'd order one of these, you'll need it to put the springs back in. can't use the hammer method for that sadly.

https://www.ebay.com/itm/Kit-Overhead-Valve-Spring-Installer-Remover-Tool-OHV-OHC-Compressor-Engines/263584654535?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

I grabbed that one for the virago. works fine. half the price of the best deal I could find on CAD side of the interwebs.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 12, 2019, 14:07:56
$15?  At that price they're making me buy it.  Thanks for the link mate - I'll see how far I can get with my buddies set up, pretty sure he has everything I'll need.  But that kit won't break the bank and would be a good addition to my shop.  No worries on the samples, it's all good.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Feb 12, 2019, 14:16:42
I would not use a hammer on your valve springs, especially because you will likely lose at least one keeper.   The tools are cheap and it's too easy to do to risk it.  My tool is like this.  I modified it just a bit and it has worked on every bike I've tried it on...

(https://cdn.eastwood.com/media/catalog/product/cache/1/image/412x/9df78eab33525d08d6e5fb8d27136e95/p/1/p14534.jpg)

Just compress the spring, then take a retractable magnet to the keepers  and they just pop right out.  Then do the same for putting them in, but without the magnet.

If you were trying to change them with the head on, you can fill your chambers with rope, turn the motor over until it compresses a bit, then push the springs with your hands and get the keepers out with a magnet.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 12, 2019, 16:03:46
I would not use a hammer on your valve springs, especially because you will likely lose at least one keeper.   The tools are cheap and it's too easy to do to risk it.  My tool is like this.  I modified it just a bit and it has worked on every bike I've tried it on...

(https://cdn.eastwood.com/media/catalog/product/cache/1/image/412x/9df78eab33525d08d6e5fb8d27136e95/p/1/p14534.jpg)

Just compress the spring, then take a retractable magnet to the keepers  and they just pop right out.  Then do the same for putting them in, but without the magnet.

If you were trying to change them with the head on, you can fill your chambers with rope, turn the motor over until it compresses a bit, then push the springs with your hands and get the keepers out with a magnet.

I was joking about the hammer...mostly. I have done it that way before but its definitely not the preferred method.

I've got a tool just like this, but I'm remembering that it didnt fit around the fins on the 360 when I was reassembling the top end. Mine must be a shallower throat depth.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Feb 12, 2019, 16:11:16
I was joking about the hammer...mostly. I have done it that way before but its definitely not the preferred method.

I've got a tool just like this, but I'm remembering that it didnt fit around the fins on the 360 when I was reassembling the top end. Mine must be a shallower throat depth.
Yeah, you have to modify the jaws in order to fit inside the head. It's the angle of the spring and their orientation/distance to the inside lip of the head.  Once you modify it, they pretty much fit any Honda with an ajdustment of the thumbscrew.
Title: Re: 1982 CB750F... The resto-not
Post by: cb360j on Feb 12, 2019, 16:43:29
Common motor collective sells the style I use for motorcycle heads (also the one that Maritime posted link to), not sure if it would work on a 750 but it works for 550's. Its a little easier to use in my opinion vs. the one irk mentioned (which I would use for a sbc head)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 12, 2019, 20:51:53
Valves removed no pasa nada, learnt a new thing today.  Never removed them before so good to know the process - my friend, who's a 30+ year motorbike mechanic and restorer extraordinaire, has all the tools and made swift work of it.  They were in bad shape - like brittle plastic.  Damn good job those things are out of the head and into the bin. 

I'm going to glass-bead clean the head before installing the new seals, which raises a question.  He strongly advised, using a collection of french, english and portugese words for "utterly shit", against using anything but OEM valve seals.  Same for the gaskets (base and head).  Would that be shared wisdom amongst you guys?  The generic gasket kit (which contains the valve seals as well) is gonna run me about $80.  ONE oem valve seal is going to set me back about $15, and I need 16 of the buggers.  And that's just for starters.

Are the generic gasket kits really that bad?  Anyone had any good/bad/utterly shit experience with them?
Title: Re: 1982 CB750F... The resto-not
Post by: Hurco550 on Feb 12, 2019, 21:00:12
Are the generic gasket kits really that bad?  Anyone had any good/bad/utterly shit experience with them?

If my 2 cents (USD) is worth a penny and a half, I've had good luck with winderosa kits for both 2 stroke and 4 stroke engines. I've never had an issue with any of them personally. I am also not a 30 year veteran, but thinking at it now, I rebuilt my first 2 stroke snowmobile engine 15 year ago anyways (with the close guidance of my father ;) lol

The most recent one I purchased was the complete seal and gasket kit for my xr200 and I believe it cost me 40 bux shipped. It contained every single o ring, gasket and seal that could be replaced on that engine.

Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Feb 12, 2019, 23:26:57
I get the blue viton valve seals and I try to get all viton o rings, so I get the benefit of ethanol tolerance. 
Title: Re: 1982 CB750F... The resto-not
Post by: Nybz on Feb 13, 2019, 03:24:36
Vitron all the way!
The stock ones don't hold up very well to ethanol.
Contact Genesound on the cb1100f forum....he has them on the cheap!
$15 for 16 seals plus shipping from US
He also has the upgraded cam holder bolts for cheap too

there are lots of people who only use OEM gaskets. I heard Cometic has good base and cylinder gaskets.

Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 13, 2019, 10:19:41
That's invaluable, and has saved me a load of cash, thanks guys.  I'll check out the Viton seals, and will shoot Genesound a message on that other forum.  I read somewhere that Athena's gaskets hold up pretty well, and I'll definitely check out Cometic and Winderosa.

Buying a non-branded gasket and seal kit does give me paws pause.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Feb 13, 2019, 10:23:02
I've used all three brands with great success.  There really isn't a difference material-wise in each brand gasket.  Fitment from better dies seems to be what separates most of them from each other.  Cometic will also do an MLS head gasket, which IMO is a better deal.  I use copper on most of my bored motors, but both of my 750 choppers have the graphite Cometic head gaskets.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 13, 2019, 10:29:03
I've used all three brands with great success.  There really isn't a difference material-wise in each brand gasket.  Fitment from better dies seems to be what separates most of them from each other.  Cometic will also do an MLS head gasket, which IMO is a better deal.  I use copper on most of my bored motors, but both of my 750 choppers have the graphite Cometic head gaskets.

Irk, mind expanding on this a bit - what's an MLS gasket, and when you say you use copper do you mean a copper gasket?
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Feb 13, 2019, 11:18:49
Irk, mind expanding on this a bit - what's an MLS gasket, and when you say you use copper do you mean a copper gasket?
MLS = Multi Layered Steel.  There are many that will argue that this is the most superior head gasket.  Copper is copper gasket and some will argue they are superior, while other will say the opposite.  If you anneal copper correctly, it's actually a pretty great gasket and it can used over and over.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 13, 2019, 12:22:02
Got it, thanks mate
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 13, 2019, 14:26:16
And thanks for the hook-up Nybz - I got in touch with genesound over on the other forum and will be ordering just ordered a set of his blue Viton valve seals.  Much obliged  8)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 13, 2019, 18:41:49
Was going to go pick up some stuff but we had some snow last night and, well, nope.

(https://i.imgur.com/GxaDO4g.jpg)














It's a sno-hawk  ::)
Title: Re: 1982 CB750F... The resto-not
Post by: farmer92 on Feb 13, 2019, 22:07:49
Was going to go pick up some stuff but we had some snow last night and, well, nope.

(https://i.imgur.com/GxaDO4g.jpg)














It's a sno-hawk  ::)

Almost need to convert your klr into a snowhawk

https://www.snowmobile.com/manufacturer/polaris/boivin-s-unique-snow-hawk-innovation

(https://uploads.tapatalk-cdn.com/20190214/5dc0ae4e7d16830484341a3333f781dd.jpg)
Title: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 14, 2019, 11:36:43
Car's still stuck in the back alley - rigging that ^^ up to the KLR would get me around town in style.  Missus has snow pants so she's got no excuse for not hanging off the back either.

Bummed - head's ready to pick up and the frame could go to powdercoat but until the back alley gets cleared - or I buy a vehicle waaaay more suited to Montreal winters - I'm square-wheeled.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 14, 2019, 11:56:09
Man, I miss my GTI. I had Conti ProContact all weather's on it and it did great in the snow. Only got stuck once ever, but it was much easier to push out than my truck was  ;D
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 14, 2019, 13:19:00
It's a great car, but it's getting shafted in Montreal.  If I could get some good money out of it I'd probably switch it for a decent all-wheel drive, the Mazda CX3 would do it.  But I'd be perfectly happy with a beater truck too.  It may not have the go of the gti, but all that gets me is speeding tickets anyway.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Feb 14, 2019, 13:26:26
I love my Yaris, it's almost as big inside as the GTI, half the cost to operate and I got mine for 3500 bucks with 230K Km on it and it now has 344K. After I finish lifting it and putting the AT winter rated 4 season tires on it will plow right through that.  THat being said, I'd love to have a Golf GTI too, if I could afford to operate it.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 14, 2019, 13:37:41
To be honest mate, running costs on the car are pretty good.  Hasn't cost me anything really in maintenance, and the few parts that did crap out were generally covered by extended warranties. 

That's not strictly true.  The fuel sensor crapped out a week after its warranty ran out, followed by the fuel pump shortly after.  But the service at VW has been great, along with their roadside.  Can't complain.  Smoked a wild turkey on the highway a while back (gnarly), $3000 of damage.  VW took care of it, and gave the front end a new paint job.  But you're onto something with that baja yaris man - that's the kind of vehicle I need.  Today more than ever.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 14, 2019, 13:48:14
To be honest mate, running costs on the car are pretty good.  Hasn't cost me anything really in maintenance, and the few parts that did crap out were generally covered by extended warranties. 

That's not strictly true.  The fuel sensor crapped out a week after its warranty ran out, followed by the fuel pump shortly after.  But the service at VW has been great, along with their roadside.  Can't complain.  Smoked a wild turkey on the highway a while back (gnarly), $3000 of damage.  VW took care of it, and gave the front end a new paint job.  But you're onto something with that baja yaris man - that's the kind of vehicle I need.  Today more than ever.

Mmmm... smoked turkey...

Is it lunch time yet?
Title: Re: 1982 CB750F... The resto-not
Post by: farmer92 on Feb 14, 2019, 17:01:28
Here ya go james, saw this for sale just now.
Just what you need for these lovely QC winters
(https://uploads.tapatalk-cdn.com/20190214/1ccdd5d6d3061176c9dbedd86023198c.jpg)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 15, 2019, 10:08:17
Back alley still not cleared (three days now - *&%$###$$%%$##@@@@##) so short of sticking some tracks on the thing I'm still snowbound.  May have to make that guy an offer Farmer, or take up transcendental meditation.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 16, 2019, 19:33:30
Holy crap.  Spent 2 hours on the phone to the city last night bitching about the snow in the back alley - at midnight they finally sent a plough to clear that shit out.  After three days of being stuck back there, finally - Freedom.

Full of the joys of all things liberated, jumped in the car and picked up my freshly-minted frame with its new hoop -

(https://i.imgur.com/SP3BHde.jpg)

- just like Rhonda this one is also squared off.  I think it looks great like this as opposed to one continuous semi-circular hoop, especially with the squared off K tank as well.  It's about an inch longer than Rhonda's too on the request of my wife, who got tired of sitting half on the arse end of the seat and half on the rear tail light bracket.  Gotta keep the ladies happy, am I right?  Need to get me a pipe bender and a welder, but until then Kieran's the man.  Smashed it, what a guy.  Opened up his own shop in the east of the island - not just a great guy but a moto guy through and through.  Champ.  I added the crossbrace as well which will be the mount for both the seat and the rear fender.  Hard to see in the photo but also welded in a mounting nut for the tank. 

Also got out the worst of the dents in the tank I'm going to be using on this bike -

(https://i.imgur.com/txEzwEU.jpg)

- some well-placed mud and she'll (hopefully) look spiffy.  I'm not much of a body man - I've used filler before but not with a huge amount of success.  Hopefully this tank'll come out way better than the shambles that was the '78 VW bus I fixed up once upon a time.
Title: Re: 1982 CB750F... The resto-not
Post by: trek97 on Feb 16, 2019, 19:58:39
Haha happy wife happy life.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 17, 2019, 21:00:40
Eyeing up a Nissin front brake master cylinder with a ⅝" piston diameter - can anyone tell me if that's the right piston for this bike?  It has two calipers up front.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 18, 2019, 10:25:43
I think I can answer my own question - ⅝" would pump more fluid and therefore be the right option for a dual caliper set up, no?
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Feb 18, 2019, 10:40:50
I think I can answer my own question - ⅝" would pump more fluid and therefore be the right option for a dual caliper set up, no?
You size your mc bore based on caliper area.  So technically, if you have a one piston caliper of 20 sq cm and a dual small piston caliper of the same area, then the m/c bore would be the same.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 18, 2019, 10:50:18
Makes sense Irk - I should find out the caliper area first then?
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 19, 2019, 19:21:05
Got the call from the machine shop, head's now looking spiffy after a glass bead clean.  They also repaired the buggered spark plug thread, and cleaned up the others which, to be fair, were grateful for the attention -

(https://i.imgur.com/XTT3MNA.jpg)

Not sure what they're called but the little wells that the valves sit in look brand new -

(https://i.imgur.com/fWNGVTo.jpg)

- and that can only be a good thing.  Waiting on my Viton valve seals to show, then this puppy gets rebuilt.  Also discovered that the overhead cam chain tensioner (the bowed plastic part) has a huge crack in it.  So turns out pulling the head really has been a good idea. 

Fucking hell it's cold in my garage.  Quite frankly a witch's tit sounds cozy compared to my garage.  Shnuggling up in a witch's cleavage sounds absolutely horrific whatever the situation, but definitely warmer than the absolute zero that is my garage.  Fuck.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Feb 19, 2019, 19:42:24
It doesn't look very cold.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 19, 2019, 20:08:10
It doesn't look very cold.
No?  I guess that's something then.  At least I'm not transmitting the deep freeze through the wonders of the internet.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Feb 19, 2019, 21:20:19
Its fucking -32f or some shit with windchill. Its cold
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 19, 2019, 21:32:00
It's fucking madness Mike is what it is.  "Divide it east to west, it'll be brilliant" said no Canadian ever.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Feb 19, 2019, 22:12:25
Yep. Thank god for 7.9% abv winter warmer pi
nts 😁
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 20, 2019, 11:15:06
I thank god for lots of things this time of year - thermal underwear, bourbon, eventual snowplows...but this morning, receiving photos of a mate's holiday villa in sunny Costa Rica via WhatsApp, shit.  I'm not thanking god for WhatsApp today.

Now that the head's all pretty it's time to reinstall the valves.  This'll be the first time I've done this so before I get started does anyone have any tips or must do's (or do nots)?  The valves have all been numbered so I know where they all go - first thing I gotta do is lap them.  I'll pick up some paste today - are they all pretty much the same?  I can get this from Canadian Tire -

(https://i.imgur.com/ZwGqGh9.png)

- and also the little suction cup tool.  Anything I should know, I'm absolutely all ears.

Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Feb 20, 2019, 11:24:16
Do not over do it. Honda valves have a coating to harden them and if you grind it all off they will wear exponentially faster. I would install them and if they seat without leaking, don't even lap them. if they seep a little, lap only those ones.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 20, 2019, 11:59:00
Do not over do it. Honda valves have a coating to harden them and if you grind it all off they will wear exponentially faster. I would install them and if they seat without leaking, don't even lap them. if they seep a little, lap only those ones.
"Seat without leaking" - from what I've learnt, this can be checked by installing the valves into the guides (no seals, springs etc), filling the combustion chamber with water, press down on all four valves, and then blow air into the intake/exhaust port.  Any bubbles will show where the valve needs to be lapped more.  Is this the (or at least, a) way to check the seats?
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 20, 2019, 12:07:09
I've always done isopropyl in the ports, and see if they seep. I do it before I take the valve springs and keepers off.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Feb 20, 2019, 12:08:55
^ That's for testing leaks on the valve seats.  For the guides, I stick my finger over the seal and pull the valve out.  It should make a *pop* off your finger.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 20, 2019, 12:14:24
^ That's for testing leaks on the valve seats.  For the guides, I stick my finger over the seal and pull the valve out.  It should make a *pop* off your finger.
Actually Irk that's what I'm testing for - leaks on the valve seats.  The head has been cleaned (as have the seats) but the valves, not so much.  They're pretty cruddy.  So my understanding is that lapping the valves will ensure a better seal in the seat.  To check for good seating I've been told the process I mentioned earlier is a good one.  Would you guys agree?
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 20, 2019, 12:36:55
Also, ordered an Athena gasket kit from vintagecb750.com last night, and found out that they're based here in Canada.  Bingo.  No duties.  Colossal win.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Feb 20, 2019, 12:58:37
Actually Irk that's what I'm testing for - leaks on the valve seats.  The head has been cleaned (as have the seats) but the valves, not so much.  They're pretty cruddy.  So my understanding is that lapping the valves will ensure a better seal in the seat.  To check for good seating I've been told the process I mentioned earlier is a good one.  Would you guys agree?
I've always tested leaks on the seats the way Nick described- with springs and everything installed and 90% isopropyl in the ports, then checking for seepage.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 20, 2019, 13:03:16
Right on.  Thing is with that method, wouldn't it mean installing everything, finding a leak, then taking it all apart again?  The air-blow method seems a bit more immediate in terms of results, and it doesn't involve installing everything. 
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 20, 2019, 13:05:58
Right on.  Thing is with that method, wouldn't it mean installing everything, finding a leak, then taking it all apart again?  The air-blow method seems a bit more immediate in terms of results, and it doesn't involve installing everything.

Yep, that's why I check for leaking valves before I disassemble  ;)

Never heard of the method you're talking about but it may work?
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 20, 2019, 13:13:24
Never heard of the method you're talking about but it may work?
It better!  ;D

Wife's step father gave me a Makita air compressor which he bought for some framing project or other which never happened.  It's not got a huge capacity but it definitely blows air - bought a small air gun and will put this method to the test.  I'll see if I can rig up some kind of video too.
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Feb 20, 2019, 14:53:09
A tried and  true way to check the seat while youre lapping is to use machinist dye on the seat.  as you lap the valve it will wear off showing the high spots, lap until you have an even ring. You can also use a sharpie if you donít have dye
Title: Re: 1982 CB750F... The resto-not
Post by: Nybz on Feb 20, 2019, 14:56:36
I found the air gun to not be accurate enough to check for leaks.
After replacing pitted valves faces and lapping only the one that were leaking, I had installed all valves, springs and keepers, filled the combustion face wth water and I blew about 40psi air up in the ports and saw some bubbles in pretty much all of the valves...some a lot and some not so much.

After I filled the faces with alcohol and left them for a few hours and only found one or two valves that were leaking and needed alittle bit more lapping.

Make sure you get allllll that lapping compound cleaned out...trust me you donít want that running in your cylinders.

Also with springs and everything installed try tapping the end of the valve with a soft hammer to open and close the valve a few times before testing for leaks. If anything is under there, it can give you trouble.


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 21, 2019, 11:31:09
Thanks for the info and tips guys.  Nipped out last night and picked up the lapping compound and tool, and spent a while watching a few vids on how to do the job.  Seems like doing it by hand (as opposed to using a drill with suction cup) is the preferred method, at least for a newbie.  That way you get a better feel for the process, and can hear the changing sound a well-seated valve makes in its seat.  Apparently - I'll find out one way or another.

I don't have the mechanics dye so I'll use a Sharpie on the seat.  If I understand correctly - sharpie the seat, lap the valve, and once the sharpie is removed evenly from the seat then I'm in business?
Title: Re: 1982 CB750F... The resto-not
Post by: trek97 on Feb 21, 2019, 16:39:43
I found the suction cup on my new tool was too glossy and would slip on the valve. 

I roughed it up w some emory paper and that did the trick.

(http://www.dotheton.com/gallery/11494-011118174021-4611922.jpeg)
(http://www.dotheton.com/gallery/11494-011118174021-4612867.jpeg)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 21, 2019, 17:26:53
Thanks for the tip Trek - I'll be in the garage later if I don't swerve for a pint or two of stout instead.  That could happen.  It would not be the first time by any means.

Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Feb 22, 2019, 04:07:12
Thanks for the info and tips guys.  Nipped out last night and picked up the lapping compound and tool, and spent a while watching a few vids on how to do the job.  Seems like doing it by hand (as opposed to using a drill with suction cup) is the preferred method, at least for a newbie.  That way you get a better feel for the process, and can hear the changing sound a well-seated valve makes in its seat.  Apparently - I'll find out one way or another.

I don't have the mechanics dye so I'll use a Sharpie on the seat.  If I understand correctly - sharpie the seat, lap the valve, and once the sharpie is removed evenly from the seat then I'm in business?


pretty much.

Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 22, 2019, 10:06:04
Thanks Doc - I got a couple done last night with the guidance of a friend whoís an old hand at this kind of thing. Slow and steady definitely wins the race. I need to check the Clymers and see if it indicates how wide a band I want to see on the valve seating surface (on the valve itself) but I now know itís not much, no more than 1mm wide I think.

Itís a very satisfying job thatís for sure - the sound of the grinding compound as it changes from grainy to smooth, knowing the improvements that will be felt once the bikeís back on the road and that engineís roaring away - time well spent.


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F... The resto-not
Post by: Nybz on Feb 23, 2019, 04:29:37
Yup!


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Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 25, 2019, 10:43:15
Valve lapping.  On a long list of moto-related jobs I've enjoyed in the workshop that is right up there.  It's just so damn satisfying.  Here's a before -

(https://i.imgur.com/ouBtGq2.jpg)

Hooked up a brass wire wheel to the bench grinder, being careful not to brush the actual seating surface too much, or above the join where the valve meets the stem.  They clean up pretty good -

(https://i.imgur.com/5VZZPxL.jpg)

Some grinding compound on the valve and its corresponding seat, a minute or so spinning the lapping tool - lifting the valve up and off the seat and rotating it through 180 degrees every now and then - and they come out looking like this -

(https://i.imgur.com/jHyy4SM.jpg)

That's what you're looking for - an even grey ring around the valve.  Anyone unfamiliar with the valve geometry (as I was) - note that the seating surface is pretty narrow.  There are a few angles to the valve, one of which is the actual seating surface (please correct me if that's wrong), and that's the angle you're lapping.  The band isn't wide - from my understanding it's around 1mm.  So softly softly catchee monkey kinda deal when you're lapping.  I did it by hand - there are vids out there showing guys with drills but that all looks a bit aggressive particularly if it's your first time doing it.  Lapping by hand gives a really good feel of the process, plus you can hear the grinding compound breaking down too, which is good.

Here's a before of the valve seat -

(https://i.imgur.com/k4jhQBJ.jpg)

And here's an after -

(https://i.imgur.com/Rm5QTKE.jpg)

I sharpie'd the valve and the seat after lapping - spinning the valve in its seat then shows any high/low spots where the sharpie has not been ground off.  Again, that clean grey ring is a good indicator that your valve is lapped and seating well.  Next - rebuild the valves and do the leak test, but that's for another day.

Also, I don't know what I was thinking.  Looked at the cylinder block, looked at the gasket set I'd received in the mail and pulled it.  I mean, shit.  Got this far, may as well do it properly.  Block came off without any drama -

(https://i.imgur.com/8hmyz8b.jpg)

(https://i.imgur.com/PgyyvLn.jpg)

- and I could then give the pistons a decent clean -

(https://i.imgur.com/sVEzlfL.jpg)

Decent enough anyway.  I'm not going to remove the pistons I don't think, but all the rings are off and bagged - I'll check out the gaps but all being well they're within spec and re-useable.  The block will get a hone - would it be a good idea to glass bead clean the block too?  Seem to remember reading somewhere that media-cleaning blocks may or may not be a good idea.

Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Feb 25, 2019, 10:53:14
In for a penny and all that. Looks good. I think you should end up with a good strong runner when done.  As for media, the fins etc are ok, don't blast in the jugs, that's what the hone is for and you'll be fine.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 25, 2019, 11:02:19

Decent enough anyway.  I'm not going to remove the pistons I don't think, but all the rings are off and bagged - I'll check out the gaps but all being well they're within spec and re-useable.  The block will get a hone - would it be a good idea to glass bead clean the block too?  Seem to remember reading somewhere that media-cleaning blocks may or may not be a good idea.

Looks good Jim. I need to lap in the exhaust valve on the 50. Been a while since I've done one as my last couple projects have needed the seats cut  ::)

I'd go ahead and bead the cylinder. I've done it a bunch. Trick is to clean the hell out of it with soapy water after your done blasting (don't want any leftover media in the bores), then blow it off with compressed air to dry it and lightly oil the bores so they don't flash rust.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 25, 2019, 11:08:30
Cool - I'll get the block honed and beaded.  I remember the cylinder on the KLR flash rusting almost immediately after cleaning it, but wiping it down with some oil stopped it from going any further.  If I buy/borrow the honing tool is it a pretty easy job?
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 25, 2019, 11:38:27
Cool - I'll get the block honed and beaded.  I remember the cylinder on the KLR flash rusting almost immediately after cleaning it, but wiping it down with some oil stopped it from going any further.  If I buy/borrow the honing tool is it a pretty easy job?

Yeah, you just want to put a cross hatch on the cylinder walls to break the glaze. Couple of the old in/outs pretty quick should do it.
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Feb 26, 2019, 12:21:56
make sure you clean the piston ring grooves really well. Carbon is highly abrasive and if there are loose bits in there it will break your rings down quickly. Nice work.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 26, 2019, 12:33:10
Cheers Doc - I've been cramming a q-tip with some carb cleaner into the grooves to clean them up as much as possible.  Any other methods I'm ears - the pistons won't be coming off the con rods though I don't think.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 26, 2019, 12:35:21
Cheers Doc - I've been cramming a q-tip with some carb cleaner into the grooves to clean them up as much as possible.  Any other methods I'm ears - the pistons won't be coming off the con rods though I don't think.

What I do when I'm re-ringing is take an old ring (one from each groove) and break it into a small 1-2" piece, file the end down so its not going to gouge the piston and run that along the groove to clean out any carbon.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 26, 2019, 12:42:52
That would do it, but I'm hoping the rings are in good shape and that I can reuse them.  Bad idea?
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Feb 26, 2019, 12:59:46
That would do it, but I'm hoping the rings are in good shape and that I can reuse them.  Bad idea?

Not necessarily, the end gap needs to be checked and if they're out of spec you'll need to replace them. Really all the piston and cylinder clearances should be measured while you have the whole thing apart.  I pull a cylinder off I will usually re-ring and hone.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Feb 26, 2019, 13:04:31
Only need to re-ring if they measure out of spec on any one of the dimensions. Gap, thickness etc. and those have ranges so if your close to the good side of the range, keep em, if you are close to the almost worn side but still good, consider changing em. And of course if out of spec all together new is a must.
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Feb 27, 2019, 05:17:07
all sound advice.

I had to rebuild a top end twice last year because I assumed the pistons rings would be good to reuse because it had decent compression before tear down. It smoked a bit after the rebuild, despite having great compression and it was leaking less than 1% on all cylinders.

My point is; you don't know its good unless you check. Its not much more effort once you're in there.  If you don't want to buy the tool to measure the cylinder bore properly, get cozy with your local machine shop. My experience has been if you go in chat it up a bit and ask some informed questions they will typically go out of their way to give you a hand with your project as so few people work on their own engines in this fashion anymore.
Title: Re: 1982 CB750F... The resto-not
Post by: farmer92 on Feb 27, 2019, 07:05:11
Rings are cheap vs the time and disappointment it takes to tear it all down a second time.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Feb 27, 2019, 09:51:28
Donít get me wrong guys - Iím absolutely going to be checking the rings, pistons and cylinders. And if anything is out of spec then itíll be getting replaced/machined for sure.

Iíll see if I can borrow the required tools, and Doc youíre right - I get a lot of help from a few local shops for exactly that reason it seems. I ask a ton of questions, and the pros I know donít seem to mind taking the time to help me out.

Viton valve seals showed up yesterday - now that theyíre here Iíll give the head a good clean again, reinstall the valves, check the shim clearances and get everything ready for paint.


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Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 01, 2019, 12:58:20
By a rather circuitous and very fortunate manner I scored a set of cams from a 900F yesterday - I've read that they are a straight swap into the head and give some pretty noticeable power gains (while at the same time a bit of a drop off in the low end).  I'm trying to understand how that happens however.  Is it because the lobes are machined differently to keep the valves open/closed for longer/shorter?  Or are the lobes angled differently to each other on the cam so the valves open and close at different times?  Interested to find out.

Also borrowed a tool for measuring the inside of the cylinders, and a valve spring compressor -

(https://i.imgur.com/NaOXpjT.jpg)

It's a beautiful day here in Montreal...this weather holds up, some snow starts to melt and our riding season officially starts in 2 weeks.  Ambitious, but hey.  Dusting off Rhonda and the KLR for a blat around town sounds gooood.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Mar 01, 2019, 13:09:54
Nice, I hope to get at the GL this weekend. we can ride anytime the snow is gone, but we have enough that could be May. I should be going over to the states tomorrow, I think you sent me the receipts for your stuff. If I'm missing one I'll message you.  As for the cam, there is a ton of things you can change with profile changes that effect power over all the rpms etc. Teazer would be the one here who can explain it all. The diff between the 900 and 750 if I remember is duration, lift and timing. So when the valves open, how long and how far and if the intake and exhaust overlap at all.  What the difference between the 2 is, I don't remember but I read it once.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 01, 2019, 13:35:58
Nice one Mike, my man.  Pretty sure I've sent you the invoices but I'll double back on my emails to be sure.  Once I get my hands on those powdercoat samples one of two things will happen - I'll pick out one that I like and I'm off to the races, or I'll confuse the shit out of myself and end up going gloss black.  A bit like when we painted our apartment.  "Shit, let's just paint it white, keep things easy".  Yeah, right.  The missus came back from the paint shop with 500 different whites to choose from.  So much for easy.

Hopefully Teazer will chip in with some more info, thanks for the input mate.  If the cylinders need more than a hone then the same guy that hooked me up with the 900 cams also has the 900 cylinder block too, and pistons.  It's a good job I have bottomless pockets filled with cash plucked fresh from the tree in the backyard that blossoms crisp hundreds every week.  Not.
Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Mar 01, 2019, 14:36:34
Higher performance cams, like the 900F ones you are installing usually have greater lift, this means that the valves open further, so like a water tap, the more "open" it is the great the flow, or in this case, air/fuel mixture.  The other aspects are the timing and duration of the valves being open.  Higher performance cams allow the valves to open and close for longer durations and both are open for greater overlaps.  These changes allow the engine to breath better at higher rpms for more horsepower, the trade off being that the engine breaths less efficiently at lower rpms.  If you put your cams side by side, you may see the difference between the 750 and 900 ones.  A poor analogy might be comparing  a person blowing air into a straw compared to blowing into a large pipe, the velocity of the movement in the straw will be much higher.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 01, 2019, 14:49:04
That makes sense Crabs, thanks for the explanation.  Should I be adjusting anything else when I install these cams?  Also, would I need to re-shim the valves, or would their spec remain the same as with 750 cams?

This just showed up -

(https://i.imgur.com/VQ95SfK.jpg)

Love it, just not sure it's yellow enough.

Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Mar 01, 2019, 14:56:03
You're welcome.  You have to make sure that there are no clearance issues between the valves and the pistons.  You say the cams are a drop in, just make sure that they are.  Sometimes you do have to change the valve clearances with cam changes, my Guzzi was like that.

That is a nice speedo, hope you are able to peg it :)

Brian
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Mar 01, 2019, 15:00:14
It better peg or it will be sad. that's in KPH so Max's at 84 MPH LOL ;D
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 01, 2019, 15:05:59
Oh shit you're right.  Dammit.  Note to self...buy things at 2am after a few beers - consequences.

I'm blaming it on beer anyway.

Doing the Ton will have to be measured in butt-clench instead.
Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Mar 02, 2019, 03:52:56
It better peg or it will be sad. that's in KPH so Max's at 84 MPH LOL ;D

Ha ha, I didn't notice that.
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Mar 02, 2019, 10:31:15
Surely the speedo isn't a left-over from the early 80s? I'd check to see if the vendor will do a swap.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 02, 2019, 10:44:02
Surely the speedo isn't a left-over from the early 80s? I'd check to see if the vendor will do a swap.
The only thing vintage about this thing is the guy's brain that bought it.

Still, if they're take apart-able maybe I'll just write FASTER after 140...

Edit - google says no, not really take apart-able without trashing the bezel.  Might etch the glass instead.  Either way, at the rate this build is going, I've got plenty of time to figure something out  ::)
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Mar 02, 2019, 11:16:34
Surely the speedo isn't a left-over from the early 80s? I'd check to see if the vendor will do a swap.

He is in Canada so kph is legal and if hes going faster than the 140 indicated in Quebec he'll lose his licence anyway LOL
Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Mar 02, 2019, 14:53:38
Why don't you just pry the lens off and paint MPH on top of the KPH, problem solved.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 04, 2019, 11:15:18
Can anyone tell if this would work for me?  I'm pretty sure I need a tach with a 1:4 ratio, but this is advertised as a 4:1 ratio (for old Triumphs) -

(https://i.imgur.com/jtBdHu4.jpg)

I think I know the answer already, but I really, really want to be wrong. 
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Mar 04, 2019, 11:34:39
SOHC/4 FAQ says 4:1 for tachos.

That really weirds me out that the 10, 20, 90 , and 100 are flipped.

It looks like a knockoff VDO gauge from one of the VWs

(https://i.ebayimg.com/images/g/w6QAAOSwHKpccc48/s-l1600.jpg)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 04, 2019, 13:59:58
Not sure man - the ratio for a 750 is 1:4 not 4:1.  Where did you see that SOHC's tach ratios are 4:1?  Not doubting you - in fact really hoping you're right!
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Mar 04, 2019, 14:06:39
Not sure man - the ratio for a 750 is 1:4 not 4:1.  Where did you see that SOHC's tach ratios are 4:1?  Not doubting you - in fact really hoping you're right!

http://forums.sohc4.net/index.php?topic=87443.0
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Mar 04, 2019, 14:07:37
CB750 and CB650 is 4:1, all other CB's are 20:3.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 04, 2019, 14:16:24
Well, hello snazzy tach then. 

Here's why I'm confused - DimeCity lists the tach suitable for a cb750 as 1:4.  When I contacted the seller of the tach I showed in an earlier posting however, they told me it was not suitable for a CB750, as the tach was a 4:1 - they said that a 4:1 tach and a 1:4 is not the same thing.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Mar 04, 2019, 15:52:55
Not sure the deal there, unless they went from 4:1 to 1:4  after 1978.  The stock replacements, like was Vintagecb750 sells, is 4:1. 

Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 04, 2019, 16:29:03
Maybe that's it?  4:1 for SOHC's and 1:4 for DOHC's?  Dunno man
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Mar 04, 2019, 16:39:06
Ok, think about it. The engines spin near 10 k. Do you think they want the cable spinning 40k RPM?
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 04, 2019, 16:41:59
Ok, think about it. The engines spin near 10 k. Do you think they want the cable spinning 40k RPM?
Sorry mate, mind expanding on that? 

Feel like I should know what you're talking about but, don't.

4:1?  1:4?  Both are options apparently, as i said.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Mar 04, 2019, 16:50:41
I believe that a 4:1 ratio means for every 4 revolutions of the engine, the tacho cable or whatever gears inside the tacho that register the RPMs would do one revolution. So if you're doing 8k RPM, the cable is spinning 2k times per minute.

In a 1:4 ratio, the cable would be turning 4 times for every 1 revolution on the engine. So at 8k RPM your cable would be spinning 32k times per minute.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 04, 2019, 16:54:29
Ok, thanks for that explanation.  Still none the wiser though as to which ratio I need for the bike - some sites say 1:4, others 4:1.  Pidjones - I'm thinking about it, just utterly non-plussed.
Title: Re: 1982 CB750F... The resto-not
Post by: teazer on Mar 04, 2019, 18:28:41
Are we sure that any tacho runs faster than engine speed?  That makes no sense.  I suspect that 1:4 means one tacho cable revolution per engine revolution and 4:1 means 4 engine revolutions per tacho revolution.  The same thing.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 04, 2019, 18:34:05
Are we sure that any tacho runs faster than engine speed?  That makes no sense.  I suspect that 1:4 means one tacho cable revolution per engine revolution and 4:1 means 4 engine revolutions per tacho revolution.  The same thing.
Yeah, it's crazy pills time.  What's thrown me is that I bought a 1:4 tach from Dime City for another DOHC Honda (they list all their tachs 1:2, 1:4, 1:7 etc etc), and yet I contacted the seller of the Triumph repro tach (in the image a few posts ago) that told me it was a 4:1 ratio, and that 4:1 and 1:4 were not the same thing.  He told me the tach would not work on my bike for that reason.

WTF?
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Mar 04, 2019, 20:31:22
Yeah, it's crazy pills time.  What's thrown me is that I bought a 1:4 tach from Dime City for another DOHC Honda (they list all their tachs 1:2, 1:4, 1:7 etc etc), and yet I contacted the seller of the Triumph repro tach (in the image a few posts ago) that told me it was a 4:1 ratio, and that 4:1 and 1:4 were not the same thing.  He told me the tach would not work on my bike for that reason.

WTF?

I think you need to buy and test them both so we can figure this out once and for all   ;D
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 04, 2019, 20:39:56
I think you need to buy and test them both so we can figure this out once and for all   ;D
That.  Then maybe I can finally answer the question pidjones keeps asking me  ::)
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Mar 04, 2019, 21:15:53
Or get a Speedhut and it won't matter.
Title: Re: 1982 CB750F... The resto-not
Post by: canyoncarver on Mar 04, 2019, 21:25:18
Or get a Speedhut and it won't matter.

See, that's what I was thinking.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 04, 2019, 21:33:58
Had to google speedhut - ah to have deep pockets, then lots of things wonít matter.


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F... The resto-not
Post by: cxman on Mar 05, 2019, 07:16:11
4to1 for all the 750 dohc and sohc
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 05, 2019, 10:38:23
Thanks for all your input guys.  There seems to be a bit of a conflict surrounding the ratio, someplaces it's listed as 4:1, others as 1:4.  What compounded the head*ck - for me anyway - is that I was told by a seller of a 4:1 ratio'd tach that it would not work for me as I needed a 1:4, and the two ratios were not the same thing.  Screw it.

The voodoo- hoodoo- what you don't dare do- people.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Mar 05, 2019, 11:02:15
get an electronic tach and plug the tach hole and be done with ratio's all together.

Edit* I have a cheap china one and it works fine, every so often my engine revs to 1500000 rpm for a second but generally shows the correct revs LOL. There are good quaity for decent prices and all you need is to wrap a lead on the coil or plug wire and your done.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 05, 2019, 11:10:08
Thanks for the suggestion Mike, I'll look into them.  Does yours have a digital display?  Do all the electronic tachs have digital displays?
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Mar 05, 2019, 11:10:48
Here's the gauge cluster for a stock 1970 Triumph Bonneville.  Notice the ratio printed on the face of the gauge.  Homeboy that is arguing this info is an idiot.

(http://www.bikesrestored.com/wp-content/uploads/2015/05/triumphbonneville-1970-9.jpg)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 05, 2019, 11:15:03
Thanks Irk - the dude telling me that 1:4 is not the same thing (and therefore non-compatible) as 4:1 has really thrown the cat amongst the pigeons, yeah.  He's the seller of the Emgo Triumph repro tach (which is 4:1), and he's the guy telling me it won't work on my ride (which, I've been told, is both 1:4 and 4:1 - depending on who you ask).

So I guess the million dollar question is - is 4:1 the same thing as 1:4?

Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Mar 05, 2019, 11:23:08
Thanks for the suggestion Mike, I'll look into them.  Does yours have a digital display?  Do all the electronic tachs have digital displays?

You can get analog dial with needle that run off spark readings. It just might save you headaches. May make things worse IDK for sure LOL.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Mar 05, 2019, 11:26:32
There are better ones than this but here is a 5 sec ebay search for one:

https://www.ebay.com/itm/NEW-Style-Universal-Motorcycle-Tachometer-Tacho-Gauge-Speedometer/172870436378?epid=2250903503&hash=item283fe1861a:g:ojkAAOSwlddcdobm
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Mar 05, 2019, 11:28:02
When the two CB750's that I currently own and the other that I did own changes from 4:1 to 1:4, I'll let you know.  ;)
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Mar 05, 2019, 11:29:10
then again the next one down was this:
https://www.ebay.com/itm/Mini-Universal-Motorcycle-Mechanical-12K-RPM-Tach-Tachometer-Gauge-1-4/151666316926?epid=1537126653&hash=item235004567e:g:iZgAAOSws0pcFjL4

fits CB750 and is 1:4 and I am not sure if it's correct or not.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 05, 2019, 11:34:12
When the two CB750's that I currently own and the other that I did own changes from 4:1 to 1:4, I'll let you know.  ;)
Ha!  I'm not doubting you Irk, I'm just confused by what I reading.  The tach that Dime City sells for CB750's is listed as 1:4 (as are a lot on eBay etc).  And this dude selling the Triumph repro tach tells me his is a 4:1 and therefore won't work with my bike.  It just all got a bit confusing and by a bit I mean a whole shitload.
Title: Re: 1982 CB750F... The resto-not
Post by: Nybz on Mar 05, 2019, 13:09:03
4:1 for all stock CB750 DOHC or SOHC ....donít know where the 1:4 came from, typo probably.
You are all good


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Mar 05, 2019, 16:36:54
Are you sure it's not 5:1?  ;)
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Mar 05, 2019, 19:10:24
I still contend that on an engine that can spin to 10k, no one is going to design a tach that requires the tach cable to spin at 40,000 RPM.
Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Mar 05, 2019, 19:12:16
What Pj says would seem to make sense.

 
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 05, 2019, 19:27:29
What Pj says would seem to make sense.
Concur wholeheartedly.  Think I've explained by now where the confusion stems from however, so I'm going to do everyone a favour and never say the words tach or ratio ever again in the same sentence. 

Might not say them individually either.  Bollocks to both of them  ;D
Title: Re: 1982 CB750F... The resto-not
Post by: cxman on Mar 06, 2019, 08:36:58

"I still contend that on an engine that can spin to 10k, no one is going to design a tach that requires the tach cable to spin at 40,000 RPM."

what could go wrong????

Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 07, 2019, 19:02:02
Entry-level question - bearing in mind that I'l be cramming whichever engine part will fit into my very small shop oven to cure the paint, is there a particular kind of masking tape I should use to stand up to the heat or would regular painter's tape do the job?
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Mar 07, 2019, 21:14:07
i just peel off the masking tape before I bake. there is also high temp powder coating tape.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 07, 2019, 21:48:27
D'oh.  Remove it before baking!  I scare myself sometimes. 
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Mar 07, 2019, 23:50:03
D'oh.  Remove it before baking!  I scare myself sometimes.

I always try to pull tape when the paint is still pretty fresh, too. Usually whenever the can says "dries to the touch". I've seen some paints (rattle can) that like to chip if you pull the tape after its cured for a day. But that also could have been caused other factors.

Who knows? But that's how I do it anyways.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 08, 2019, 10:46:44
Removing the tape before baking is absolutely what I'll do.  Just feel a bit daft asking a question with such an obvious answer.  Still, no such thing as a silly question - something I have to remind myself when I have a d'oh moment  :o
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Mar 08, 2019, 11:19:48
I always try to pull tape when the paint is still pretty fresh, too. Usually whenever the can says "dries to the touch". I've seen some paints (rattle can) that like to chip if you pull the tape after its cured for a day. But that also could have been caused other factors.

Who knows? But that's how I do it anyways.
+ one or even a little sooner, nothing worse than pulling tape and having an edge flake off a nice clean job.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 10, 2019, 12:14:22
After a closer look at the mating surfaces on the cylinder block and head, it's clear that they're going to need a bit of a hone to clean them up a bit.  Plan is to tape some sandpaper onto the granite countertop in the kitchen (before or after the missus cooks her breakfast - all bets are off.  If this is my last post, she wasn't happy), lower the mating surface onto it and give it a clean. 

What would be the best grade sandpaper to use?  I'm thinking 1000 grit?
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 10, 2019, 12:21:50
Finished up the fins on the head -

(https://i.imgur.com/QkGPiwB.jpg)

Filed them to get a flat profile (cheers for the tip Maritime), sanded them (400, 600, 1000 then 2000) and then polished (red compound ("tripoli"), then white compound ("diamond") then Autosol).  Came up aces.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Mar 10, 2019, 13:08:27
Nice. And I cant take credit. I read to file somewhere on the vastness of the interwebs LOL. Just passed it on after trying it.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 11, 2019, 12:31:31
Well, yesterday was mating surfaces day.  Turns out, you never see mating surfaces day coming.  One minute you're in front of the telly watching footie with a mate, the next you're taping sand paper to the kitchen countertops.  Mating surfaces day.  You never see it coming.

I ended up using 240 grit first, then 400.  Asked Mrs K if she was cool with me bringing half my engine into the kitchen and having at it with a couple sheets of sandpaper, and when I say asked I mean didn't ask.  Taped up the paper like so -

(https://i.imgur.com/JxP63v0.jpg?1)

and lowered the cylinder block onto it.  For the first time since remodelling the kitchen I found myself agreeing with my wife that there wasn't enough counterspace (I didn't know what the hell she was talking about - now I do) - really could've used another sheet in there for more of a "slide".  No matter, it's all good.  Here's what it looked like before -

(https://i.imgur.com/JuzTBzC.jpg?1)

and here's the after -

(https://i.imgur.com/ViQKX21.jpg?2)

Not perfect (couldn't shift those couple of darker areas) but a load better.  Pretty sure I can live with it.

The head was a bit trickier - the exhaust studs stuck out a little too far and meant I'd fuck up the granite in double quick time.  Had a re-think, dug out a collage my lovely and highly arty wife made for me years ago and taped some paper to that instead -

(https://i.imgur.com/Yi9MuAs.jpg)

- the thick glass made it perfect for getting into the hard to reach places and kept a uniform flat surface.  Don't have a before an after of the head but it came up good too.  Hauled everything back into the garage, got out a stanley and cleaned up the gasket from the cylinder block -

(https://i.imgur.com/8TXJMsv.jpg)

Surfaces...mated.  Ready for mating anyway.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Mar 11, 2019, 14:24:33
Just curious, but did you check the true on that countertop?  Curious how close it is to a proper surface plate.  Most surface plates are several inches thick to accommodate flex from the surface it sits on, as well as being ground to within .0000025"
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 11, 2019, 14:28:22
Also dug out the large o-rings that sit in the recesses around each cylinder underneath the block.  They were no longer rubber - snapped like plastic as I pried them out.  35 years will do that to an o-ring.

Thanks to a care package that arrived last week (cheers Maritime) I now have my repro Triumph bars, stainless engine bolts, valve cover bolt seals and powdercoat samples.  Really threw a curveball at myself when deciding about a colour for the frame, but wanted to try something a little different.  The tank is going to be a green gold, and I think I'm going with this for the frame -

. https://www.youtube.com/watch?v=Wtmktb7uSoI

It's pretty much black, but looks gold in some angles.  Could work, one way to find out.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 11, 2019, 14:31:03
Just curious, but did you check the true on that countertop?  Curious how close it is to a proper surface plate.  Most surface plates are several inches thick to accommodate flex from the surface it sits on, as well as being ground to within .0000025"
I'm curious now too - I had to take a punt on it being true as it's the only thing in my world that's even close.
Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Mar 11, 2019, 16:34:12
Do you have a straight edge that you can use to check the surfaces with now?
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 11, 2019, 16:48:20
Here's what I got -

(https://i.imgur.com/M8rMdDh.jpg)

The ruler is the straightest edged thing I've got, but I'm not 100% convinced it's perfectly straight-edged.  I can see daylight between the ruler and the granite, but barely. Maybe 0.1mm?
Title: Re: 1982 CB750F... The resto-not
Post by: Nybz on Mar 11, 2019, 20:02:31
I found out the hard way on my goldwing, when I attempted to straighten the head a back and forth motion was not the way to do it, but instead a circular motion. Otherwise there is too much pressure on one side doing it back and forth.
I had to take it to a machinist to flatten it back out.

Good luck!


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Mar 11, 2019, 21:54:40
a sheet of glass is supposed to be flat, can you try that, also flip your straight edge over and see if you get the same results.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Mar 11, 2019, 22:01:24
a sheet of glass is supposed to be flat, can you try that, also flip your straight edge over and see if you get the same results.
Technically, float glass is the truest surface of glass, but it's not.  It's way more true than his counter, but not as true as a surface plate.  I've used thick panes of it for similar purposes in the past, but nothing like the mating surface of a head.  All glass is prone to bow and warp, so there is a range of tolerance when it comes to ASTM standard.
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Mar 11, 2019, 22:14:11
A 12" square of 1/4" plate glass with 600 grit spray-glued on worked well on the Hunley head and block. Used Dychem to see the high spots until it showed flat. My surface block was good for seeing if a feeler would fit under. Final testing with Prusian Blue to make sure.
Title: Re: 1982 CB750F... The resto-not
Post by: wozza on Mar 11, 2019, 22:30:14
Good old fashioned oil stone oil and figure 8's is how Ive always done it..never had an issue......
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Mar 12, 2019, 05:00:40
You could always have a machinist mill a little off the head to make sure its flat and get a boost in compression at the same time, seems like a no brainer to me :-X
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Mar 12, 2019, 09:14:36
Here we go again

(https://myocddiaries.files.wordpress.com/2013/11/alice-falling-down-rabbit-hole1.jpg)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 12, 2019, 10:03:56
Ha! You know what, Iím starting to get pretty comfortable down this rabbit hole. Who the hell knows where itíll end, but Iím enjoying finding out.

I really appreciate and value the input fellas. Time maybe for a plan b.


Sent from my iPhone using DO THE TON
Title: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 12, 2019, 17:01:58
Going to do it proper.  Went to my man's shop who has Ĺ" thick plate glass just for this job.  Tried removing the exhaust studs that are getting in the way - 2 came out no problem but the others didn't budge, even with a heat gun.  Had to down tools but will get more heat on it tomorrow, double-nut the stud and see if I can get those little buggers out.
Title: Re: 1982 CB750F... The resto-not
Post by: V10Pilot on Mar 13, 2019, 10:39:56
Drained some of the oil, wasn't milky or weird smelling and tried setting setting it on fire but didn't light so pretty sure there's no gas in there.  Rebuilt the carbs, jammed them back in the bike and hooked up Rhonda's tank as a stand-in.  Don't mind the enormous fairing up front, slung that on for shits and giggles...

https://youtu.be/-EHuxVzExoc

Getting a non-runner to start for the first time is a feeling like no other.  Love it.  Took a while to fire, but that's because (I think) of the empty float bowls and vacuum petcock set-up.  You may be able to see the can sitting on the frame - that's Honda carb/combustion chamber cleaner and it's good stuff.  Much thicker than regular carb cleaner which - for whatever reason - works really well (guess it sticks around longer, burns slower?).  Either way, with the airbox not connected to the carbs and a good 5-10 seconds of that stuff sprayed into the carb body and it's off to the races.

The bike sounds pretty damn good too, no weird rattles, clanks or leaks yet.  Did see that one of the spark plug threads is cross-threaded so I guess I'm going to have to pull the head and re-tap it or get a TimeSert in there .  Other than that, so far, so good.  Will check compression tomorrow, but all four pipes were nice and hot (ie totally burnt myself on all of them) - including the cylinder with the cross-threaded spark plug.

Included in the vid is a close up of the air filter housing.  Me and my wife have a jewelry business - if I find a skull in amongst the rats nest in there I'm casting it in bronze and it's going on this bike.

Sweet.  So now that I know it runs I'm gonna do the basics on her to the point where she'll pass her safety inspection, then bring her home and get the grinders out.  Good people - onwards  8)
That front fairing looks like it belongs on a golf cart!

A running engine is a great feeling. The value just went up 300%.


Sent from my iPhone using DO THE TON (http://r.tapatalk.com/byo?rid=89466)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 13, 2019, 12:31:10
Damn, that was a while ago - bike's in a million pieces all over my garage now!  Forgotten how the engine sounds it's been so long - man I'm looking forward to hearing it again.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 13, 2019, 22:02:01
Working on re-doing the mating surfaces (turns out I was wrong about the other day being mating surfaces day.  Wasn't even close).  Took the head and cylinder block to my friend's shop and spent at least two hours honing them on his glass surface.  Now I have a much better understanding of the amount of work involved, and of course the importance of the true nature of the honing surface.  They look waaay better now - I'll post up some photos tomorrow.

Tried "breaking the glaze" in the cylinders too.  The lines that the tool created in the cylinders however are all concentric (like a thousand tiny rings all stacked eon top of each other).  I thought however the rings were supposed to be cross-hatched but I don't see how to make that happen with the drill spinning like it is.  How important is it to get that cross hatched hone in the cylinder?  I know (I think) it is to aid to movement of oil on the cylinder wall.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Mar 13, 2019, 22:33:36
I think to get cross hatch you need to move the hone up and down in the cylinder quickly. Don't spin it in place.
 
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Mar 14, 2019, 07:51:05
Youtube can demonstrate: https://youtu.be/myeKVBH5ALc
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 14, 2019, 10:49:26
Thanks for the video - that's pretty much exactly what we did but didn't get the cross-hatching.  Drill spinning too quickly?
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Mar 14, 2019, 11:22:53
Thanks for the video - that's pretty much exactly what we did but didn't get the cross-hatching.  Drill spinning too quickly?

Possibly. I brought the XL350's top end to a machine shop and he honed it while I waited. The hone machine was going slow, probably less than 500 rpm.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 14, 2019, 11:34:19
Yeah, I think that's it.  Need to dial down the drill.  Even with the fine grit stones I'm guessing the honing tool removes material from the inside of the sleeve, and so overdoing it is a no-no?
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Mar 14, 2019, 12:12:21
Yeah, I think that's it.  Need to dial down the drill.  Even with the fine grit stones I'm guessing the honing tool removes material from the inside of the sleeve, and so overdoing it is a no-no?

Yep. You basically want to go the least amount possible to get a good 45 degree cross hatch.
Title: Re: 1982 CB750F... The resto-not
Post by: cxman on Mar 14, 2019, 19:32:30
get a ball hone or some call them flex hones

with the 3 jaw hones you will bell mouth the cylinder before you get nice crosshatch

a well lubed ball hone you are done in a minute less than 1/2 thou removed

and the cylinder is degalzed and cross hatched
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 17, 2019, 11:57:52
Worked on the brake calipers yesterday, man they're crusty.  Thankfully I now have a small air compressor in the garage so getting the pistons out wasn't too much trouble, but one did need some encouragement from some pliers to get it past the roached seals.  The piston is slightly scratched and I'm pretty sure I can clean it up with some fine grit sandpaper and some Autosol metal polish.  Is that cool?  I'll be careful no to remove any material from the piston - just the scratch.

The seal grooves inside each caliper are in pretty rough shape too, and the seals were all completely destroyed (whoever rode this beast last must have had zero heel left on their boots - I think that must've been the only way they got this thing to slow down).  I used mechanic's picks to remove all the crud in there, and will let them sit in some clean brake fluid for a while too.  Is there anything else I can/should do to get these thing clean before rebuilding them?

The rear brake master cylinder however was in the worst shape.  The thing just looks awful - all the seals are toast and it's covered in crystallized brake fluid.  Once I got the boot off to dig out the circlip, it looked full of rust and the circlip ain't budging for love or money - in fact it shattered my circlip pliers trying to remove it.  Any ideas on how I can get that thing out?  Tried soaking it in PB Blaster to - so far - no avail.
Title: Re: 1982 CB750F... The resto-not
Post by: cxman on Mar 17, 2019, 20:01:07
boil it in water that covers the master cylinder  with 2oz of lemon juice that will loosen most of it up

boil for 10- 15 minutes then try removing the ring while its hot
Title: Re: 1982 CB750F... The resto-not
Post by: stroker crazy on Mar 17, 2019, 21:30:03
A slow but sure method to remove rust without damaging good metal is to soak it in a mix of one part molasses to eight parts water.
Animal feed molasses is marginally better than that meant for human consumption.
Remove part from the mix every now and then to brush off dissolved rust.

An oldie but a goldie!
(specially on sheet metal when you can't afford make it any thinner)

Crazy
Title: Re: 1982 CB750F... The resto-not
Post by: cxman on Mar 18, 2019, 07:13:55
only the rod is steel the master body is aluminum ish
Title: Re: 1982 CB750F... The resto-not
Post by: stroker crazy on Mar 18, 2019, 07:34:12
the molasses mix won't hurt the alloy ...
Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Mar 18, 2019, 11:39:59
Would either of these products work, without damaging the aluminum?

https://www.canadiantire.ca/en/pdp/metal-rescue-rust-remover-bath-3-78-l-0477920p.0477920.html?gclid=Cj0KCQjwg73kBRDVARIsAF-kEH9MFJkUa1bubZN41y5wIdyEow9vCYGz2duyCiqfnT9O1EUVjDtlGJoaAjz1EALw_wcB&gclsrc=aw.ds#store=606

https://www.uline.ca/Product/Detail/S-18420/Cleaning-Supplies/CLR-Calcium-Lime-and-Rust-Remover-828-mL-Bottle?pricode=YE390&gadtype=pla&id=S-18420&gclid=Cj0KCQjwg73kBRDVARIsAF-kEH9MLxFTryfW6qdTE_VMp7bemlSKiV-NnNJbdFuvv__d4Km-oGPBzrMaAhq2EALw_wcB&gclsrc=aw.ds
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Mar 18, 2019, 12:18:12
Vinegar?

You'll probably have to break that circlip to get it out. They are a PITA to reach with snap ring pliers and even if you can get to them they never want to come out. The last MC I rebuilt I broke the circlip into pieces and pulled out the chunks. Replacing it is easy as you can use the snap ring pliers to get it to fit in the bore, and then use a socket thats close to the same diameter as the bore to push it down evenly until it seats.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 18, 2019, 12:32:09
Thanks guys - I ended up leaving the thing soaking in PB Blaster overnight and then attacking the circlip with a couple of mechanics picks.  Wrestled that thing out, then had to manhandle the piston and its washer.  Man what a mess.  Still, got it all out and hopefully the master cylinder itself will be salvageable.  The bores cleaned up ok -

(https://i.imgur.com/DfvIPNb.jpg)
(https://i.imgur.com/ew7ZsFX.jpg)

Good to learn about those rust-shifting techniques.  I've used Metal Rescue before on a rusty gas tank - that stuff is the business.  Has one job to do, and does it brilliantly.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 18, 2019, 12:53:31
Uncovered a bit of a mystery too yesterday.  After measuring the cylinder bores it looked like all of them were out of spec, and larger than the wear limit specified in the Clymers manual.  Although my first reaction was to get the hump knowing I was going to have to shell out on an overbore and new pistons, I then thought to check the piston diameter.  I hadn't removed the pistons from the con rods so that was the first job (no circlips took a dive into the crankcase, but boy did they try) - no drama. 

Then measured them.  Here's the table showing the piston diameter, and the corresponding bore diameter -

(https://i.imgur.com/EEKi9KX.jpg?1)

All the ring gaps were within spec (at least they were when referencing the stock ring gap specs in Clymers).  Could it be that the cylinders have already been bored and new, larger pistons installed?  I mean, I can't think of any other scenario really.  I don't know how stock pistons are marked, but the ones in my engine are marked "25" (albeit faintly) on the top -

(https://i.imgur.com/OlWwJRz.jpg)

and "425 8" on the side -

(https://i.imgur.com/WhSsBY5.jpg)

I know they're OEM as they're marked Honda on the other side -

(https://i.imgur.com/detG8BI.jpg)

Any ideas?

Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Mar 18, 2019, 13:10:08
I'd think that the "25" on the crown could possibly mean .25mm overbore which is first over. Can you check your measurements with the manual and compare? If you add .25 to the specs in the manual do the numbers make more sense? There should also be a piston to cylinder clearance value that should hold true even in the case of an overbore.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Mar 18, 2019, 13:14:29
You're consistant with .003 on each piston for clearance so they very well could be overbore pistons and the machine shop matches the bore to each piston when they do it. the ring gap is the ring gap no matter the piston size, the ring Diameter however would be larger than stock so see if you can find the 1 over sizes and that may be what you have already.  It would make sense that you got good ring gap measurements on the rings if this was a recent overbore.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 18, 2019, 13:28:27
Thanks fellas - I've dug up what I can on the internet and it looks like the "25" marking on the top of the piston may well be the indicator that a .25mm overbore has been performed on the engine.  Haven't found anything conclusive yet, but things are pointing in that direction. 

I'll check out the specs again and re-jig the numbers allowing for the extra .25mm.  Hopefully all will point to these being over-size.  The compression on the engine was excellent (165psi across all cylinders) so I guess this could be part of the reason - the thing is I'm just not experienced enough to know (or look out for) the tells that the engine has been opened up and worked on. 
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Mar 18, 2019, 18:24:01
the easiest tell-tale sign that an engine has been opened up is the gasket surfaces have already been scraped. I would run those pistons with zero worry, however new rings may not be a bad idea as you can see that carbon has been getting past the first ring. Not the end of the world, but not ideal either. And definitely get new circlips.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 18, 2019, 18:38:22
Cheers Doc, gotta say that's a huge comfort.  If you'd run these pistons with zero worry that's more than enough for me.  I'll look into a new set of rings - when you say circlips are you talking about the circlips on the wrist pins?  Why would they need to be replaced?  Metal fatigue?
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Mar 19, 2019, 01:58:55
Cheers Doc, gotta say that's a huge comfort.  If you'd run these pistons with zero worry that's more than enough for me.  I'll look into a new set of rings - when you say circlips are you talking about the circlips on the wrist pins?  Why would they need to be replaced?  Metal fatigue?
yeah the wrist pin circlips. getting them out can cause them to loose spring tension. its not something you want to pop out while the engine is running. Its cheap insurance.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 19, 2019, 10:57:07
Was having a late night look at some photos of the head and cylinder block (before I honed them) and noticed something I'd missed before.  There's what looks like an 'overspill' pattern of carbon that is exactly the same on the top of each cylinder -

(https://i.imgur.com/cfBkUuN.jpg)

close up -

(https://i.imgur.com/MGcOSbZ.jpg)

What would cause that?  Knowing now that the cylinders have - at some point, not very recently judging by what little info I got from the PO when I bought the bike - been overbored and the pistons switched out with .25mm larger ones, would this have happened after the piston switch?  I'm assuming yes of course, in which case what would have caused it?  Poorly fitted gasket?  Poorly honed mating surfaces?  Is it normal perhaps?  Very interested to learn more about this.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Mar 19, 2019, 10:59:11
Looks like it could be just an abnormally shaped aftermarket head gasket. Since there is no blowby it wouldn't be caused by a leaky head gasket or bad mating surfaces.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 19, 2019, 11:05:33
Blow-by...what exactly is that?  Oil that gets past the rings?
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Mar 19, 2019, 11:21:02
Blow-by...what exactly is that?  Oil that gets past the rings?

I'm not using the correct terminology. What you mentioned is blowby, but I'm talking about what you would see from a leaky head gasket.

This is a VW engine but same concept:

(http://www.ratwell.com/technical/Heads/GasketFailure.jpg)
Title: Re: 1982 CB750F... The resto-not
Post by: Sonreir on Mar 19, 2019, 11:29:24
Blow-by...what exactly is that?  Oil that gets past the rings?

It's when the gases inside the combustion chamber escape in some way. Usually through a gap between the head, head gasket, and cylinder jugs.

In this case, it's just the head gasket shape and it's perfectly normal to see that pattern.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 19, 2019, 11:34:59
Brilliant, thanks gents.  Very good to know.

The build-up was fairly significant (0.5mm high maybe) - I guess that's the height of the compressed gasket in that case.  It took some work on the honing glass to get the surface totally clean. 
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 20, 2019, 20:17:41
A trip to Gabriel's always costs me a few quid I wasn't expecting to spend, but always money well spent none the less.  He's been repairing and restoring old Japanese bikes for 30+ years, so he knows his way around.  Dropped off my frame and some parts for powdercoat/glass bead cleaning, and asked him if he could flex hone my cylinders to get that nice cross hatch.  He told me he always sends his cylinders off to his machine shop connection and get it done right for $50 - didn't take long to agree that that was a very good idea.

While it's there I may get the few busted fins repaired and get the whole block glass bead cleaned too, if the price is doable.  Do it right - deal with the wallet-dent later.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 21, 2019, 11:04:58
Learnt something the other day about brake fluid.  DOT 5 is unlike DOT 3, 4 and 5.1 in that it is silicon based and not glycol-ether based.  This means alls kinds of things, one of them being DOT 5 will not attack paintwork unlike the others.

The entire brake system must be either new or completely restored (there must be no moisture in the system, nor can DOT 5 be mixed with any other kind of brake fluid) - but on all the master cylinders I've seen (at least on older bikes) it always says DOT 3 (or DOT 4) ONLY. 

Has anyone used DOT 5 in an older bike?  As long as I follow the guidelines strictly, is there anything else I should look out for? 
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Mar 21, 2019, 11:27:37
DOT 5 is actually recommended for antique vehicles because it has a much longer shelf life.  So, for anything that sits for longer periods of time (looking at you Canadians with hellacious winters) it's a better fluid to use.  Sludging is the concern if you mix the two, so definitely make sure you are putting it into a fresh system or one that has been cleaned really well.  Also, it cannot be used on modern bikes with ABS.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 21, 2019, 11:32:22
I read that Irk - definitely a no-go with ABS systems.  I'm hoping to powdercoat the brake calipers and in the process of talking about the pros and cons, the whole DOT 5 conversation came up - largely because whenever I bleed my brake lines I end up wearing half of it and getting the rest on the calipers.  Knowing DOT 5 won't attack the paint/powder is great, but now knowing that it is actually recommended for older bikes (and yeah, especially ones that hibernate for 5 months) is a real bonus.

Are there any negatives with DOT 5 fluid in older bikes? 
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 22, 2019, 11:15:23
Getting ahead of myself a little over a morning coffee but whatever.  Has anyone swapped out their 7" headlight for one of these?

(https://i.imgur.com/syzVBiI.png)

The heat sink on the back of it looks not much bigger than the stock halogen bulb so looks like it may fit in the bucket.  Would it work?

https://www.ebay.com/itm/1X-7-Round-Halo-Angel-Eye-CREE-LED-Headlight-DRL-For-Jeep-Wrangler-CJ-TJ-LJ-JK-/163590465762
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Mar 22, 2019, 11:20:33
This is a little more expensive but Matt has done all the testing and research and the quality on this one would be worth it.

http://www.sparckmoto.com/Products/Detail/100

Cheers
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 22, 2019, 13:17:34
Cheers mate, looks to be almost exactly the same but I know Matt has a very good reputation for a very good reason.  I'll definitely bear his offering in mind.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Mar 22, 2019, 13:21:20
The one you linked may be ok, but I know Matt;s will light the road correctly and not burn out in a Week LOL. I grabbed his AUX lights and they are super well made vs some things I have seen online and at like Princess Auto or CT for the same price. 
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 23, 2019, 20:19:09
Installing the valves today - all the intakes went in no problem, poured acetone into the ports and no leaks.  But I've got an acetone leak on one exhaust valve - I've pulled the thing out now three times and re-lapped it but it's still leaking.  After lapping it didn't show that nice clean grey line -

(https://i.imgur.com/DQ9OFgz.jpg?1)

- maybe a bit hard to see in the photo though.  Could it be leaking because the seat on the valve itself is no good, or perhaps the seat itself in the head?  What would I check to find out which it is - if not both?
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Mar 24, 2019, 05:18:33
whats the seat look like?
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 24, 2019, 10:33:34
It doesn't look great either -

(https://i.imgur.com/x9QH9wd.jpg?1)

- I'll try and get some better pics.  This is after 4 laps, and it still doesn't have that clean, great line that the other valves/seats have after lapping.  To compare, here's what one of my decent seats looks like -

(https://i.imgur.com/Rm5QTKE.jpg)

Guess I'm wondering what the options are now.  New valve?  Take the head to a machine shop and have them re-cut the seat?  New seat?  Or just more lapping? And what would cause this in the first place?
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Mar 25, 2019, 00:36:05
The mating surface looks pretty wide on the seat. Have you measured it? if its too wide the valve spring cannot provide adequate pressure to seal.
Title: Re: 1982 CB750F... The resto-not
Post by: cxman on Mar 25, 2019, 06:50:22
its been over heated and the valve or seat has deformed

in the dohc the valves will get sucked up into the head when over heated
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 25, 2019, 10:31:13
Thanks for the insight gents.  I think maybe I figured something out over the weekend.  While I was lapping the valves I kept finding that the the suction tool was pulling off the valve face.  I wondered if this may have been caused by one of (or both) of the following - 1. the face of the valve wasn't smooth enough and 2. the lapping compound was too thick.  So I took one of the two valves that we were leaking (the other 14 were sealing just fine) and ran the face over the brass wheel on my grinder.  Then I added a small amount of WD40 to the polishing compound - that worked a charm.

I think what was happening is that the thickness of the compound (it's also pretty cold still in my garage) was preventing me from being able to grind the compound down enough while lapping the valve, as the suction tool would pop off before it got thin enough.  By adding the oil, it lubricated the lap more and therefore the lapping compound broke down completely.  When I reinstalled the two valves that had been leaking before and filled the port with acetone guess what...no leaks. 

With the valves installed I moved on to the forks.  To anyone reading this that hasn't disassembled these forks before it's a really easy job with the right tools - but (as I found out on my last CB750) a right pain in the arse without them.  The good news is, the right tools turn out to be not too many tools at all.  Once you've got the oil and long spring out (there are two springs in there), clamp the lower tube in your vise.  There's a 6mm allen bolt at the bottom of the lower fork tube - chances are you won't be able to remove it as it's bolted to a stem that sits underneath the long spring (in the bottom of the lower tube).  Turning the bolt will just spin that stem.  Here's where the other tool comes in - a broom.  Shove the broom down the upper tube and put pressure on that stem sitting in the lower tube.  With pressure on the stem you can then engage the allen bolt and unscrew it.  For the visually motivated (like me) -

(https://i.imgur.com/izuwzCZ.jpg)

Remove the fork from the vise, and tip out the stem (there will be a smaller spring on this stem too - if it doesn't come out with the stem then it'll be stuck (loosely) on the bottom of the lower tube, easily removed).  Then you can remove the dust seal, the large circlip (I use a couple of mechanic's picks to get that out), and slide the upper tube in a kind of slidehammer motion to ease out the fork seal.  Job's a good'un. 
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 26, 2019, 00:15:45
Breaking the bank -

(https://i.imgur.com/xGWqWAF.jpg)
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Mar 26, 2019, 15:04:31
I've found that if you remove that Allen bolt FIRST (but after draining), you don't need to worry about the the inside spinning. Loosen the top cap afterward (carefully). An air impact is good for getting the Allen loose quickly.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 26, 2019, 20:44:26
That definitely sounds like a good method.  My broom - utterly ignored as it is anyway - just got even more redundant.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 27, 2019, 21:35:35
Carbs disassembled -

(https://i.imgur.com/ZJGpz5b.jpg)

and lording it up in their PineSol tubs -

(https://i.imgur.com/wCS4m3i.jpg)

Damn stuff stinks.  Rather them than me.
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Mar 27, 2019, 22:28:26
Keep 'em separate - good! Do you plan to put them through an ultrasonic?
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 28, 2019, 00:32:11
I wasn't planning on it - 24hrs in the pinesol and then a thorough clean.  I have Mike Nixon's booklet on how to clean these carbs, it's an excellent step-by-step.
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Mar 28, 2019, 07:52:04
There is a great CB750 carb rebuild procedure pdf by SeanG on cb750c.com: http://www.cb750c.com/publicdocs/SeanG/Honda_Carb_Manual_revG.pdf (don't know if a direct link works, but you can try). It stresses thorough cleaning of the slow speed jets and pilot circuit. My accelerator jets were plugged solid, eve with sonication and carb cleaner under pressure. I ended up with the finest guitar string I had (high G from a 12 string) in a pin vice to reach from the outlet end with butterfly open and finally hit the tiny hole to clear it, then a liberal flush of carb cleaner. But, mine had been sitting since 1999. I also had to solder up two of my overflow tubes due to cracks. I made a temp fuel supply with 91% isopropyl alcohol for leak testing. Less stink, evaporates well, mixes and burns if any is left. To test for cracked overflow tubes, fill each with alcohol over a sink with the bowl drain closed. Nothing should come out the drain. If it does, inspect carefully for a crack running up the tube. I soldered mine.
Title: Re: 1982 CB750F... The resto-not
Post by: cxman on Mar 28, 2019, 08:29:14
i just drill the tubes out and press in new ones

i had to fix 8 float bowls last week

when checking for leaks have a look at the tip of the drain screws with our

wonderful ethanol fuel the water in the carb goes to the lowest point in the bowl

right around the tip of the screw and eats the screw sometimes causing a leak if its disturbed

the factory screws are steel and get corroded

i use brass drain screws when i replace them  that i get from sirius sonic inc

https://www.siriusconinc.com/pro-detail.php?pid=&product_id=1371

they seal up great never stick either

Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 28, 2019, 10:56:10
Thanks guys, that's really great info.  I have some drain screws on order and already have rebuild kits for the carbs - I've emailed Sean to see if he he still has o rings and screw sets.  That's a helluva walk-thru pidjones, many thanks for the link.  Invaluable, and a great companion to the Mike Nixon booklet I have.  Thanks again gents.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Mar 29, 2019, 09:24:54
Emailed Sean and indeed he does still sell the o-ring kit and screw set. Great price too. Thanks again for the hook-up!


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Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 08, 2019, 19:26:15
Lots of good stuff showing up recently (thanks in no small part to Maritime, thanks mate - owe you so many beers now) -

(https://i.imgur.com/8AGZpfG.jpg?1)

- carb and piston parts, engine gaskets, bolts and oil seals, cam chain tensioner, valve cover bolt seals and caliper rebuild kits.  Also picked up my freshly powder coated frame and calipers -

(https://i.imgur.com/PkU6t8d.jpg)
(https://i.imgur.com/uUW9g4X.jpg)

- chose an old bronze, slightly metallic colour - snazzy.  Gloss black for the frame - I've powder coated a few frames now but have to say the gloss black really is something.  Guess there's a good reason it's the go-to.  No photos (everything's still glad-wrapped) but I'll get some up soon.

Also picked up a bunch of parts and engine covers from glass bead cleaning -

(https://i.imgur.com/TfS3I4y.jpg)

- thing's look brand new.  First time for me, but won't be the last.  To think I spent weeks (literally) cleaning and sanding these things on my last CB to get them to a state not even half this good - glass bead for the win.  More snazz.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Apr 08, 2019, 20:34:32
Looking good Jim. Blasting is definitely the way to go, hand cleaning one air cooled engine was more than enough for me. Are you going to paint the engine bits?

I have yet to get any cool colors of powder, but its on the list.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 08, 2019, 21:34:50
Plan is to polish the engine covers, lump itself will be satin black with polished fins.

You got any idea what grade sandpaper I should start with?  I'm thinking pretty high (hopefully) as I don't want to create any more work for myself than necessary.  Obvs.

As the entire brake system is going to be essentially brand new, I'm going to use DOT 5 which apparently won't bugger up paint/powder when I predictably spill it all over the bike.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Apr 08, 2019, 21:47:50
Plan is to polish the engine covers, lump itself will be satin black with polished fins.

You got any idea what grade sandpaper I should start with?  I'm thinking pretty high (hopefully) as I don't want to create any more work for myself than necessary.  Obvs.

As the entire brake system is going to be essentially brand new, I'm going to use DOT 5 which apparently won't bugger up paint/powder when I predictably spill it all over the bike.

Let me know how the powder holds up. I'm going to powdercoat the brake backing plates for the bus and was worried about that.

Try polishing the blasted surface and see how it comes out. You may get lucky.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 08, 2019, 21:53:00
Will do.  Not too worried about damaging the powder with the brake fluid, but wondering how it'll hold up against the heat.  I'll let you know mate.  If I can get away with polishing the covers without any sanding then I'm in like Flynn.  One way to find out.
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Apr 09, 2019, 00:03:33

You got any idea what grade sandpaper I should start with?  I'm thinking pretty high (hopefully) as I don't want to create any more work for myself than necessary.  Obvs.


I think that ship already sailed. most media blasting will make make the surface textured and take more elbow grease to get out. I would start will 220 and go from there. It usually saves time to start fairly low and work your way up in as small of steps as possible, working in a crosshatch pattern.
Or alternatively if you have a buffer with some good torque, you can take it to 320 and get a pretty good polish with the right mix of wheels and rouge, the high speed buffers kind of "melt" the surface on aluminum so you don't have to polish very high to get a good finish.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 09, 2019, 00:12:10
I think youíre right
Probably will need a ton of work, but it was nice being in denial for a while.


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Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Apr 09, 2019, 01:48:18
Looks great but I particularly like the way the calipers turned out.  :)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 09, 2019, 10:27:15
Cheers mate - I nearly powdered the whole frame that colour but bottled it.  The tank'll have some colour too it and at the 25 hour I though it might all be a bit too much.  But yeah, colour looks pretty sweet on the calipers, and definitely very happy to hear about DOT 5 not damaging painted or powdered surfaces.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Apr 09, 2019, 10:29:09
Probably a good idea to do the colour in smaller doses on the bits and gloss black frame. It will fall to the background and the other bits will pop.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 09, 2019, 11:00:25
Aye, I think somewhere in the back of my mind that was the swing vote Mike. 

Going back to the DOT 5 thing, the Nissan master cylinder I'm looking at makes a big song and dance about how it's not compatible with DOT 5 fluid, but I can't find much evidence or reasoning to back this up.  Is it just a throw-back to some bygone era that simply poo-poo's anything but DOT 3 or 4 (I think any master cylinder I've seen all have something like "use only DOT 3 or DOT 4 from a sealed container" written on the lid) being used?  Is there a reason for saying DOT 5 is not compatible - might it effect the rubber seals in the master cylinder?  Or is it something more nefarious - master cylinder manufacturers wanting us to use DOT 3 or DOT 4 so the seals do wear out and therefore force us to buy new parts?  Or is that just cynical?
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Apr 09, 2019, 11:07:11
IDK re DOT 5 vs 4 vs 3 but it could be as simple as when that master was produced it wasnt testes on 5 or 5 wasnt around. My mid eighties cbr600 says DOT 3 only, but the other fluids were not available so maybe I can use 5. Rumor has it you can put the newer stuff in older systems but not the other way around. Ive not found a trusted source on that yet. I think Irk has a reference on it that may confirm.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Apr 09, 2019, 11:11:53
Quick google: http://collision.alldata.com/online2help/shopOps/Inspection_Forms,_System_Checklists_and_Customer_Questions/Answers_to_Common_Customer_Questions/Brakes/can_dot_5_brake_fluid_be_used_instead_of_dot_3_or_41.htm

I didnt vet the source but sounds legit and I think its what Irk said in an earlier post. Hes smart enough to trust most of the time ;D
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Apr 09, 2019, 11:21:08
From what I've read, 5 is a silicone based brake fluid and has a higher boiling point than 3-4. Because it is silicon and not glycol based (like 3-4) it does not absorb water and reportedly does not ruin paint. People have been running it in older systems for years without problems. The only thing you'd have to worry about is if it eats the seals, which I would think would happen pretty quickly if it were going to.

https://www.thesamba.com/vw/forum/viewtopic.php?t=409242&highlight=dot5
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 09, 2019, 11:21:28
I've done a bit of research into the make-up and advantages and disadvantages of the different fluids so I now know a bit more about their application.  What I'm trying to understand is the first line of that link Mike - "Always refer to vehicle owner's manual for what the manufacturer recommends or warns against".  The manufacturer (Nissin) is recommending against DOT 5 (or says that DOT 5 is not compatible) but I'm trying to figure out why.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Apr 09, 2019, 11:23:35
I've done a bit of research into the make-up and advantages and disadvantages of the different fluids so I now know a bit more about their application.  What I'm trying to understand is the first line of that link Mike - "Always refer to vehicle owner's manual for what the manufacturer recommends or warns against".  The manufacturer (Nissin) is recommending against DOT 5 (or says that DOT 5 is not compatible) but I'm trying to figure out why.

Jim, does it say "DOT 3 or 4 ONLY" or "DO NOT USE DOT 5"?

Like I said the only worry would be it eating seals, so maybe they know that the rubber they used isn't compatible with the silicone based fluid. But I've never heard of that happening before.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 09, 2019, 11:26:03
The only thing you'd have to worry about is if it eats the seals, which I would think would happen pretty quickly if it were going to.
That's what I'm thinking - DOT 5 may bugger up the seals in the master cylinder.  Of course there's one way to find out, but the cylinder I'm eyeballing is not exactly cheap  :o

Would DOT 5 really attack the seals in a master cylinder?  Seems counter-intuitive that brake fluid would attack rubber seals in a brake system, bit of a design flaw, amiright?
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Apr 09, 2019, 11:32:09
That's what I'm thinking - DOT 5 may bugger up the seals in the master cylinder.  Of course there's one way to find out, but the cylinder I'm eyeballing is not exactly cheap  :o

Would DOT 5 really attack the seals in a master cylinder?  Seems counter-intuitive that brake fluid would attack rubber seals in a brake system, bit of a design flaw, amiright?

I honestly doubt it would, but that's the only potential issue I could see. I've never heard of it actually happening before. I would just put it in and go with it.
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Apr 09, 2019, 11:32:51
i think mastercylinders usually say don't use DOT 5 because is not compatible with DOT 3 & 4 and that is what they assume the system to have been bled with from the factory. if its a fresh system i think you're good to go.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Apr 09, 2019, 11:33:02
Did the bike it came off of have ABS originally, that would be why it would say no DOT 5.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 09, 2019, 11:33:22
Jim, does it say "DOT 3 or 4 ONLY" or "DO NOT USE DOT 5"?

Like I said the only worry would be it eating seals, so maybe they know that the rubber they used isn't compatible with the silicone based fluid. But I've never heard of that happening before.
Good question - it depends what website I'm looking at.  The lid on the cylinder itself says "Use only DOT 4 from a sealed container" rah rah rah, and the item description (on some websites) says it's not compatible with DOT 5.  I'll be purchasing the cylinder from a different (cheaper!) site, but here's another link -

https://4into1.com/nissin-retro-master-cylinder-black-w-black-lever-5-8-piston/
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Apr 09, 2019, 11:44:37
Did the bike it came off of have ABS originally, that would be why it would say no DOT 5.

Just saw your link. it's new so that wouldn't be the issue. the article I linked said DOT 5 compresses different and reacts different so the piston design in this may be the issue, won't compress the same, to much i.e. instant lock, or to little, smooshy brakes or none at all. 

I doubt it's an issue with eating seals. or like Doc said, they are covering their butts assuming you have DOT3-4 already and you can't mix 5 in with that. It may be just fine if you have an all dry system to start and go 5. email 4-1 and see what they say to that.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Apr 09, 2019, 11:58:51
I thought DOT5 was designed for use in ABS systems?

Anyways, if it says specifically on there that its "not compatible with DOT 5", then why risk it?

Product info on a master cylinder doesn't assume that you have DOT3/4 in your brake system. They don't care. If they say "not compatible with DOT 5," then theyre probably saying their internals either haven't been tested with DOT5 or have been tested and are not compatible.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Apr 09, 2019, 12:11:16
Wow, this brake fluid conversation may just trump the internet's plethora of motor oil conversations. 
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 09, 2019, 12:19:09
My understanding Nick is that it's the other way round - DOT 5 is not compatible with ABS.

Why risk it?  Good question.  I don't want to risk anything, especially when it comes to stopping this thing when it's hurtling down the highway.  But from what I now understand DOT 5 does have several advantages over DOT 3 and 4.  It's better in brake systems that sit unused for long periods of time (like mine do, over winter), it does not absorb moisture unlike DOT 3 and 4, and it doesn't attack paintwork.  There are other benefits too - but it cannot be mixed with DOT 3 or 4 at all and so can only be used in an absolutely clean (or new) brake system.

I guess the "non-compatible" DOT 5 warnings must have something to do with the internals of the master cylinder, but as has also been pointed out it may just be that the system hasn't been properly checked with DOT 5.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 09, 2019, 12:20:12
Wow, this brake fluid conversation may just trump the internet's plethora of motor oil conversations.
Ha!  Indeed, but worthy nonetheless I hope.
Title: Re: 1982 CB750F... The resto-not
Post by: Hurco550 on Apr 09, 2019, 19:18:57
mechanical drum brakes ftw...
Title: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 09, 2019, 19:36:12
Ok, spent hours looking into this and have emailed Nissin to ask for their input.  The only plausible reason I can find for Nissin saying not to use DOT5 in the system is because it can affect natural rubber seals in the master cylinder (if indeed that is what their seals are made of).  Apparently - although this too has been disputed.  If Nissin says don't use DOT5 then I'm sure they have a reason - I hope they reply so I can move on to something far more interesting 🤯
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on Apr 09, 2019, 21:58:54
Could it be that Nissin assembles their MCs with brake fluid lubricating all rubber and sliding parts (the correct way) and therefore already has DOT 3/4 on all those parts?
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 09, 2019, 22:12:34
Thatís a very good question. And it would absolutely make sense too.


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Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 15, 2019, 18:26:28
The cylinder block is at the machine shop - I wanted to make sure that the bores and piston clearances are still in spec before honing and reassembling.  There's a significant possibility that the piston gap will be very close to the upper limit and so I may have to spring for the 0.50 oversize set (the cylinder has already been bored to 0.25 by a previous owner).  I've had a decent look online but was wondering if anyone has bought these in the past and if so have a good supplier?

There is a cheap aftermarket brand out of Australia called Forseti but there is no info on them at all so I'll probably steer clear.  Dime City, Vintagecb750, 4into1 - all the usual go-to's don't carry oversize pistons for the DOHC's.  Before I hit up ebay thought it best to ask you guys.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Apr 15, 2019, 22:41:11
Wiseco makes an 823cc kit (65mm bore) for this.  Just do it.
Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Apr 16, 2019, 00:56:34
I agree, if you are going to all the trouble of new pistons and rebore, go big bore.
Title: Re: 1982 CB750F... The resto-not
Post by: Nybz on Apr 16, 2019, 04:30:16
I got some pistons from cruzinimage. The price is right, and havenít heard terrible reviews on them, lots of people use them, and havenít heard anything about forseti good or bad....both have big bore kits.

But wiseco...... if I had the dollars to spend....




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Title: Re: 1982 CB750F... The resto-not
Post by: cxman on Apr 16, 2019, 06:56:32
find a set of cb900 cams they really light it up with the big bore kit

i have built 3 of them the latest

with a new hall effect ignition me and ray at rae-san have developed for the dohcs

using a set of 36mm dual flat slide carbs they haul
Title: Re: 1982 CB750F... The resto-not
Post by: cb250nproject on Apr 16, 2019, 07:29:13
Go the 823 cc Big Bore, its as big as you can go without re-sleeving the cylinders. Plus then if you run with the 900 cams we can compare tuning notes ;)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 16, 2019, 11:27:26
Well hello cruisinimage...just had a look at their site, thanks for the lead Nybz.  I can't believe how cheap their piston kits are - have you installed and run them yet?  I can buy all four 0.50mm oversized pistons (with rings) for $120 - that's not expensive at all compared to other kits I've seen on Ebay etc-

https://www.cruzinimage.net/2017/08/04/79-82-honda-cb750f-0-5mm-oversize-pistons-set-62-50mm/

They also have the 823cc big bore kit (inc gaskets) for $150???

https://www.cruzinimage.net/2017/08/25/79-82-honda-cb750f-823cc-bigbore-pistons-kit-65mm/

Yeah, I'm shook.

Still waiting to hear back from the machine shop - if my piston/cylinder gap is golden then all this is moot.  But if not, I think this bloke will soon be getting some of my hard-earned.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Apr 16, 2019, 11:48:31
They also have the 823cc big bore kit (inc gaskets) for $150???

https://www.cruzinimage.net/2017/08/25/79-82-honda-cb750f-823cc-bigbore-pistons-kit-65mm/

GO FORTH! For that price why even bother with stock?

Oh also, I'm gonna dig up the dead horse we already beat about brake fluid. I found this while doing some reading the other day:

Quote
DOT4 will definitely harm paint. DOT5 is silicone based fluid, which is also the one less likely to absorb moisture. Unfortunately Brembo specifically recommends against using silicone based fluids in their products, citing chemical incompatibility with the composition of their rubber. DOT3 and DOT4 are American test performance standards, not chemical content standards. In Europe and Japan (probably the rest of the world) brake fluid meeting DOT3 standards was superseded by European standards years (decades?) ago. Those European standards are what DOT4 is intended to match. Todd#389.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Apr 16, 2019, 12:13:32
Just to be an enabler. I will be over on the states for over 48 hours next weekend and wont use all my 800 tax free exemption if you want that tax free.... Has to arrive on 22nd though.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 16, 2019, 12:39:09
Shit.  Now I want my piston clearances out of spec.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 16, 2019, 13:55:40
 The pistons are still a maybe Mike, but the King Gizzard and The Lizard Wizard t-shirt I've been eyeballing is now on its way to Shiretown  8)
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Apr 16, 2019, 14:40:55
Ha, OK. I have no money to spend of my own stuff so I got $800CAD less a bottle of whisky to get tax free.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 16, 2019, 14:51:07
Good on ya mate - I'm going to find out about this piston situation and will let you know.  Can't have you crossing that border empty handed...
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Apr 16, 2019, 14:53:20
for sure, 15% is 15% and I'll give that to anyone when I can't take advantage of it.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 25, 2019, 13:58:44
Finally heard back from the machine shop - the cylinder/piston clearances are right at the outer edge of spec - pre hone.  So that's that decision made.  If the jugs need to be bored then why the hell not go all out - 823cc piston kit here I come.  Because whoever said "why?" to "more horsepower sir?"
Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Apr 25, 2019, 16:48:53
I think you will be happier with bigger pistons.
Title: Re: 1982 CB750F... The resto-not
Post by: Nybz on Apr 26, 2019, 03:39:00
I have installed but not run my pistons from them. (I should get on that)
When the machine shop measured them, only one was slightly different then the rest.
I havenít heard any horror stories, with lots of people using them, so I figured itís all good






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Title: Re: 1982 CB750F... The resto-not
Post by: cb250nproject on Apr 26, 2019, 06:24:32
Finally heard back from the machine shop - the cylinder/piston clearances are right at the outer edge of spec - pre hone.  So that's that decision made.  If the jugs need to be bored then why the hell not go all out - 823cc piston kit here I come.  Because whoever said "why?" to "more horsepower sir?"
Hell yea


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Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 28, 2019, 14:33:51
Carbs cleaned, rebuilt with new gaskets etc and reassembled -

(https://i.imgur.com/pxSlEz4.jpg)

(https://i.imgur.com/T4ZYW8A.jpg)

Here's the choke linkage -

(https://i.imgur.com/T9HRHDY.jpg)

I found this time that the choke butterflies weren't actuating when I tested the choke assembly.  Turns out it's very easy to skew the alignment of the two choke "stems" going through the carbs, and also the butterflies themselves can bind against the inside of the carb bodies.  When I bolted on the two long brackets that hold the bank together, this threw the alignment out of whack and the choke assembly seized up.  I found that by loosely bolting on the rear bracket first (and continually checking that the choke operated) and then the front one, I could then tighten everything up while also keeping the alignment good and the choke working as advertised.

The float bowls and carb hats (whatever they're called) will get a decent polish later on, but for now this job's a good'un.
Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Apr 28, 2019, 18:12:26
Nicely done.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Apr 28, 2019, 22:34:09
Looks good. Shocks should be there tomorrow. Bus arrived as I finished signing the paperwork.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 29, 2019, 13:51:29
Mmmmm, pretties...

(https://i.imgur.com/GaSePgH.jpg?1)

Not gonna lie, been eyeing up piggyback shocks for years and figured now was as good as time as any to give these a shot.  They're made by TEC Alloy, and if they work half as well as they look then I'll be very happy.  Damn things even smell good.  Adjustable damping and pre load, adjustable ride height - once they're installed and ridden for a while I'll be back with a ride report.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Apr 29, 2019, 14:11:21
Let me know, those would be great on the GL. I have CB900F shocks on it now, but they are 27 years old LOL. I was tempted to open those and fondle them before I sent them but resisted. ;D
Title: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 29, 2019, 14:16:30
I was tempted to open those and fondle them before I sent them but resisted. ;D

You've got more resolve than me mate.  I'd've had them out the box lickety-split  ;D

Thanks again Mike - I'll keep you posted.  From what I've read these things really are pretty decent, especially for the money.  The build quality looks excellent, but it's about how the rubber meets the road yada yada.  Until then, I'm fondling.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Apr 29, 2019, 14:19:53
Thanks, a first hand report is worth a lot. After riding the Big GS BMW on vacation Jill's been asking if I can get better suspension for the GL LOL
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Apr 29, 2019, 14:20:41
Those at 199.99 US is about top of my budget. I want Hagons but they are like 500 or so and that's almost half the value of the bike.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 29, 2019, 14:26:45
Those at 199.99 US is about top of my budget. I want Hagons but they are like 500 or so and that's almost half the value of the bike.
You and me both.  I bought Progressive Series 12 shocks for my last CB at around $350 US, thought I'd change things up a bit this time.  Once they're installed and I've figured out how to get the best out of them adjustment-wise it'll be interesting to see how they compare.  Plus there's a guy here on DTT who rebuilds them to a higher quality spec as well for a very reasonable price - a good option too.

And, did I mention they're pretty?  ;)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 30, 2019, 11:20:35
Need to get some braided steel brake lines ordered.  Dime City sells custom lengths of Galfer which would fit the bill, anyone know of any good cheaper options?  I'm at about $200 with DCC for the front (two calipers) and rear, that's for the lines and banjos. 
Title: Re: 1982 CB750F... The resto-not
Post by: canyoncarver on Apr 30, 2019, 11:24:35
Need to get some braided steel brake lines ordered.  Dime City sells custom lengths of Galfer which would fit the bill, anyone know of any good cheaper options?  I'm at about $200 with DCC for the front (two calipers) and rear, that's for the lines and banjos.

HEL is where I always order my hydraulic brake lines.   Excellent quality and fit.
http://www.helperformance.us/
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Apr 30, 2019, 11:39:36
Need to get some braided steel brake lines ordered.  Dime City sells custom lengths of Galfer which would fit the bill, anyone know of any good cheaper options?  I'm at about $200 with DCC for the front (two calipers) and rear, that's for the lines and banjos.

I ordered Russell brake line and fittings from Summit Racing and made my own on the 360. Cost me around $35-40 for a 27" front brake line with fittings and banjo bolts.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Apr 30, 2019, 11:39:40
Instead of banjo bolts, I run 3AN fittings in the calipers and MC, then measure the right length and find a Russell or Earls line to match.  They come in most lengths in inch increments.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 30, 2019, 12:38:17
Great, cheers.  All good info, Summit Racing seems to have a pretty good selection.  If I end up making these things myself, would it simply be a matter of choosing the right length line and banjos?  Do the banjos simply screw in to the 3AN female threads on the end of the brake line?

I'm looking at something like this for the line -

https://www.summitracing.com/int/parts/rus-656022

and this for the banjo -

https://www.summitracing.com/int/parts/rus-r4056c

That's it, that's all?
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Apr 30, 2019, 12:45:45
Great, cheers.  All good info, Summit Racing seems to have a pretty good selection.  If I end up making these things myself, would it simply be a matter of choosing the right length line and banjos?  Do the banjos simply screw in to the 3AN female threads on the end of the brake line?

I'm looking at something like this for the line -

https://www.summitracing.com/int/parts/rus-656022

and this for the banjo -

https://www.summitracing.com/int/parts/rus-r4056c

That's it, that's all?

Pretty much. You can either get the -3AN to banjo fittings or -3AN to 3AN that screw directly into the caliper/MC without using banjos and crush washers. Totally up to you. I like to use a banjo at the MC and the 3AN at the caliper, but thats just personal preference. They also make the fittings in various angles for different setups.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 30, 2019, 12:49:26
This 3AN is new to me...is 3AN the male and -3AN the female?
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Apr 30, 2019, 16:35:17
I got a gaffer or galfer kit for around 50 us I think that was a double banjo and eliminated the front splitter for the gl. Be very similar for cb. Ill look it up and see I may be misremembering a bit
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 30, 2019, 18:44:05
Is eliminating the front splitter is a good idea Mike?  I may well go that route too if yes.  The Galfer set up I saw on Dime City was going to run me two bills US in total - three lines up front and one for the rear (including all the banjos).
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Apr 30, 2019, 19:38:51
I like this dude, the Romaniac.  Think I might build myself one of these...

. https://youtu.be/mpJTTO8X0qs
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Apr 30, 2019, 19:50:12
Is eliminating the front splitter is a good idea Mike?  I may well go that route too if yes.  The Galfer set up I saw on Dime City was going to run me two bills US in total - three lines up front and one for the rear (including all the banjos).
Yeah makes bleeding way easier and jisr cleans the front up
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Apr 30, 2019, 21:27:00
This is how my chopper is set up on the back brake. With 3AN fittings. I always run a splitter on dual calipers, because they keep the pressure balanced.




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Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 01, 2019, 10:10:03
Ok cool, I'm not familiar with the 3AN-bolt-directly-into-the-caliper method, I thought it was banjos or bust.  Good to know.  Are there any advantages to the 3AN system over banjos?
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on May 01, 2019, 10:23:22
Ok cool, I'm not familiar with the 3AN-bolt-directly-into-the-caliper method, I thought it was banjos or bust.  Good to know.  Are there any advantages to the 3AN system over banjos?

You eliminate the need for banjos and crush washers, so I guess there's less chances for a leak?
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 01, 2019, 10:45:03
Good point
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 01, 2019, 14:34:07
Well I'll be dipped in shit.  Only ordered these mid last week from Japan and they just showed up now -

(https://i.imgur.com/uarVni3.jpg?1)

Gotta love the Nihonjin.  They look great, quality looks top notch and, for the money ($150 for the 823cc overbore set including rings, wrist pins, clips and head gasket) no complaints whatsoever.  Ordered two more sets for a friend, and no taxes at the border.  Damn, happy days.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on May 01, 2019, 14:35:07
purdy!
Title: Re: 1982 CB750F... The resto-not
Post by: teazer on May 02, 2019, 10:07:45
IRK:

Are those 10mm to AN adapters in the caliper and M/C?  You can also get hoses made up with metric straight end fittings.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on May 02, 2019, 10:27:35
IRK:

Are those 10mm to AN adapters in the caliper and M/C?  You can also get hoses made up with metric straight end fittings.
Yes, they are.  Seems to be cheaper to go with the metric to AN fittings and Russell DOT hoses.  I'm spending half of what it costs for Galfer or Venhill.  I don't think Galfer even does anything but banjo hoses.  And Venhill does the same as the Russell hoses with an AN fitting to a banjo.  I'd be interested in someone who does a line with a metric fitting to have the line be one piece.  I haven't found one yet.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 02, 2019, 18:54:35
Spanking new pistons and cylinder block with the machine shop, and while it's there they're doing me a solid and fixing the busted fins too for a good price.  Once I haul it back to my garage I can finally empty the cans of satin black paint that have been sitting on the shelf for two months onto the thing.  It might actually start to look like something.
Title: Re: 1982 CB750F... The resto-not
Post by: cb250nproject on May 02, 2019, 21:28:10
Youíll have to show us some before and after shots of the fins Iím interested to see how they come up. Are you going to run the same cams now that youíve gone to 823cc ?


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Title: Re: 1982 CB750F... The resto-not
Post by: teazer on May 02, 2019, 21:38:08
Yes, they are.  Seems to be cheaper to go with the metric to AN fittings and Russell DOT hoses.  I'm spending half of what it costs for Galfer or Venhill.  I don't think Galfer even does anything but banjo hoses.  And Venhill does the same as the Russell hoses with an AN fitting to a banjo.  I'd be interested in someone who does a line with a metric fitting to have the line be one piece.  I haven't found one yet.

There are suppliers on ebay that will make them up with almost any normal end fitting.  I have had them made with female 10mm and male 10mm.  There used to be a place in the UK that had the most amazing options of end fittings in anodized aluminum or steel, straight or banjo.  Fren turbo do teh same (or used to) but a bit expensive.

I have bought a bunch from this ebay seller.  Only issues were where I measured wrong and can't really blame a supplier for my screw ups.  http://www.ebaystores.com/Rennsport-Auto-Parts
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on May 02, 2019, 22:54:50
This 3AN is new to me...is 3AN the male and -3AN the female?

3AN is short for -3AN. AN stands for Army/Navy the 3 denotes how many sixteenths of an inch the ID of the tube is, in this instance -3AN is 3/16" ID a -4AN is 4/16 (1/4") and so on. Its worth nothing that this size is a nominal value, tube ID is often smaller than the stated size. IIRC the reason AN fittings were developed was to standardize lines across a large variety of machines, reducing the need for proprietary lines.

I personally like the Goodridge lines, which are for use with banjos. Ive setup many bikes with them and the lines are pre-fabricated  and sold in a variety of lengths.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 04, 2019, 10:12:11
Thanks Doc for the expanded info on the 3AN fittings and teaser for the link.  I'll look into my options some more and then decide, but I've learnt a lot more than I knew last week about brake lines just from your last few posts.  Cheers fellas.

cb250nproject - I have some CB 900 cams that I'll be installing instead of stock.  The situation was kinda fortuitous (for me anyway) but 900 cams are mine nonetheless.  I'm told they're a simple drop in - just need to check for any clearance issues that I may have between the cam lobes and the head.  That's on the to-do list.  Right now I'm waiting on the machine shop to finish up the cylinders, but this weekend we're doing a market down in Toronto so tools are sadly downed for the next few days.  Sucks too - it's the first bit of dry weather we've had in what seems likes weeks, so the KLR's gonna have to fidget until I'm back.
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on May 04, 2019, 18:36:16
You can buy all of the Goodridge fittings and line (Amazon lists them) and make your own to length/clocking/end type. I used their small line and banjos for the upper front on the Hunley. The line is no bigger than a throttle cable sheath.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 11, 2019, 11:23:36
Remembered that it was recommended to check clearances on the CB900 cams I'll be using.  I bought a valve spring compressor tool off amazon for $35 (and saved having to ask my long-suffering mate if I could borrow his tools again) which had one job to do and did it perfectly.  Out came the valves, dropped in the 900 cams and they fit just fine - no clearance issues.  Apparently these cast heads can have slight size differences in some areas and it's a good idea to check even though 900 cams are a straight swap -

(https://i.imgur.com/dVhth1U.jpg?1)

Looks like no drama in that dept so got the valves back in (with some more assembly lube) - hoping to get my newly-bored cylinder block back from the machine shop soon and this lump's gonna get painted.  In the meantime - Ottawa for mother-in-law's day. 
Title: Re: 1982 CB750F... The resto-not
Post by: cb250nproject on May 11, 2019, 18:36:00
Remembered that it was recommended to check clearances on the CB900 cams I'll be using.  I bought a valve spring compressor tool off amazon for $35 (and saved having to ask my long-suffering mate if I could borrow his tools again) which had one job to do and did it perfectly.  Out came the valves, dropped in the 900 cams and they fit just fine - no clearance issues.  Apparently these cast heads can have slight size differences in some areas and it's a good idea to check even though 900 cams are a straight swap -

(https://i.imgur.com/dVhth1U.jpg?1)

Looks like no drama in that dept so got the valves back in (with some more assembly lube) - hoping to get my newly-bored cylinder block back from the machine shop soon and this lump's gonna get painted.  In the meantime - Ottawa for mother-in-law's day.

Thatís very lucky that all the valve clearances were spot on what were they at ? I had a lot of issues getting the clearances within tolerance when I changed my cams over.


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Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 13, 2019, 18:27:33
Thatís very lucky that all the valve clearances were spot on what were they at ? I had a lot of issues getting the clearances within tolerance when I changed my cams over.
I dropped the cams in to check the clearances on the head itself, not the valve shims - that'll come later.
Title: Re: 1982 CB750F... The resto-not
Post by: cb250nproject on May 13, 2019, 18:38:34
I dropped the cams in to check the clearances on the head itself, not the valve shims - that'll come later.

Ahhh I c, youíll need, a pad & pencil, shim bucket tool,heaps of shims, booze and a stress ball


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Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 13, 2019, 19:05:09
Ahhh I c, youíll need, a pad & pencil, shim bucket tool,heaps of shims, booze and a stress ball
Ha!  Yeah mate, have all of those things (minus the heap of shims but I have a go-to for that).  Don't have a stress ball but do have the wife's cat, poor fucker.

I had to re-shim the valves on my last CB build so know the drill.  One trick I've learnt since is to sand down the casting ridges and polish the bucket tool as these can snag when you're getting the bugger under the cams. 
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 14, 2019, 00:49:30
I'm just gonna park this here, for my sake as well as anyone else who's down with T00L

. https://www.youtube.com/watch?v=QQ-TD8dVq1U













That's it, that's all.
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on May 14, 2019, 07:51:12
I'm just gonna park this here, for my sake as well as anyone else who's down with T00L

. https://www.youtube.com/watch?v=QQ-TD8dVq1U













That's it, that's all.
Our good friend Kanticoy was at that show.  He's a B'ham (Moody) local.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 14, 2019, 10:19:05
Our good friend Kanticoy was at that show.  He's a B'ham (Moody) local.
Heís a lucky guy. Just the audio sounds incredible - being there mustíve been something heíll never forget.


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Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 15, 2019, 13:00:06
Got the call from the machine shop - hopefully will be picking up the newly over-bored cylinder block today or tomorrow.  I'm also thinking that maybe now would be a good time to replace the A and B cam chains as well.  I forget whose build it was here on DTT that posted a vid of their 750 running but the engine sounded so sweet, no rattles from loose chains at all. 

Does anyone have any suggestions on where to look for well priced (but good quality) chains, or brands to look for and/or avoid?  I know they're not cheap but for sure I get why.  Also, how easy/complicated is it to remove the A chain and replace it with a new one (without splitting the cases)?

I found this supplier which has both for very (I think) reasonable prices, and they're also based here in Canada which is a big plus -

https://www.vintagecb750.com/products/4/engine/59/cam-chain-cam-chain-tensioners

I've emailed them to find out what brand the chains are, looks like the B chain is DID but I'm not sure about the A yet.
Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on May 15, 2019, 14:59:01
Love Tool, saw them last year.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 15, 2019, 15:48:18
Right on Crabs, I've seen them a few times and - if they actually do release their new album end of August - hope to see them again soon.  A few of us old timers are getting revved up here in MTL to go kick the f*cking roof clean off.

Waiting on this cam chain info from the seller.  The more I think about it the more I'm ok with dropping a few bucks on the things.  I want this engine to purrrrrr.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 15, 2019, 17:06:49
Heard back - the company that makes the cam chains is called Borg Warner.  From what little I found online they're very reputable and a good aftermarket option.  Anyone got any first hand real world feedback on them?
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on May 15, 2019, 18:25:49
I know Borg Warner for their turbos. 

https://youtu.be/I7IEZuSe7tc
Title: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 16, 2019, 10:51:02
So gents, anyone got the skinny on cam chains? I got chastised (read - chewed a new one) on another forum for suggesting Iíd be buying a cam chain which Iíd be opening and then installing a master link - apparently this is Not The Done Thing and cutting corners. Theyíre probably right - to do the job properly I should be splitting the cases, and installing an endless chain. What gives?


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Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on May 16, 2019, 11:13:48
Ask how many of them (themselves, not read on the internet) have used a master link and had their chain break or run for a shorter life.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 16, 2019, 11:31:09
Youíve used a master link Irk? No drama?


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Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on May 16, 2019, 11:40:16
No drama.  It's not the clip kind like we use on our drive chains.  You still have to use a press.  How in the hell do they think the factory makes them?
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on May 16, 2019, 12:21:37
From another thread -

Couple of thoughts.  If I have to use a soft link, I use a large hammer on the other side as an anvil.

Most bikes of the era use a 219 chain but that size comes in a number of different "strengths".  Some use thicker side plates and so have longer pins.  Some use thicker pins, so if you buy a link, make sure it is the right size. And if you can find one with a clip and not rivet, it's OK to use it.

Personally I've only ever used endless cam chains because I don't want to deal with the master link and if I'm replacing the cam chain then I already have the cases split for whatever reason.
Title: Re: 1982 CB750F... The resto-not
Post by: Nybz on May 16, 2019, 13:49:59
I thought splitting and assembling the cases would be more of a job then it actually was.
You are going this far, why not go the whole way?

It gave me a chance to look at the main and rod bearings which about half of them where shot. There arenít cheap though at about $200 to replace both sets.
You can also look over your gears and gear selector forks to make sure no chipped teeth or extra wear.
There are a few rubber O rings down there that could probably be replaced, and clean out your sump screen.

Also, i didnít do it cause I found out too late. But if you want the engine to purr and not rattle there are rubber dampeners in the primary shaft (that arenít shown in parts lists) that can be replaced, check the 1100f forum there is a guy there that sells them. Along with clutch basket dampeners (but you can get a cheaper kit from cb750.com)

Just watch those torque values on those case bolts, found out the hard way they arenít all the same.

The cam chains stamped with a M are the good ones.
Canít remember did you end up getting the cam chain tensioners from Brent at V&H? He sells them.

Tool rocks!


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F... The resto-not
Post by: teazer on May 16, 2019, 17:15:17
I can't tell you how long a master link will last on the street, but on a road race motor I have never had one fail - clip type or soft pin design (rivet type).  But that applies to 219 type single row chains.  On the DOHC motor with HyVo chain I have not tried to use a master link.  Last CB900 I built was stripped and bored etc so new endless chains were fitted.

As Irk said earlier, ask them how many failed master links they have personally experienced or seen in the real world. There's a lot of armchair experts out there.  If you do choose to go with a master link on a DOHC HyVo chain, make sure it is correctly rivetted and still free to move.
Title: Re: 1982 CB750F... The resto-not
Post by: cb360j on May 16, 2019, 18:53:12
Just installed a cam chain for my 360 and it was the press type. I don't know if 750s are the same way, but the links were so small that it didn't line up in the press correctly. I had to walk it back and forth between pins to get it absolutely perfect.  Makes me wish I had sprung for the motion pro one, it seems like it wouldve fit better. Just saying in case you run into the same issue.
Title: Re: 1982 CB750F... The resto-not
Post by: cxman on May 16, 2019, 21:01:09
borg warner is oem for some honda motors

the cx500/650 has borg warner timing chain
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 16, 2019, 21:34:01
I thought splitting and assembling the cases would be more of a job then it actually was.
You are going this far, why not go the whole way?
Why not indeed.

What makes me laugh is the fact that this engine had excellent compression before the teardown (160psi across all four), and the only real reason for pulling the head off was to repair a stripped spark plug thread.  Now look where I am!  Balls deep and staring into another rabbit hole.  Well, f*ck it.

For some reason or another I thought splitting the cases required specialized tools, clamps, god knows what.  But having had a decent look at the Clymers and after some schooling on another forum, I think I may have been over-egging my omelette somewhat.  No walk in the park, but not as difficult as perhaps I thought.  Not only would it obviously make the exhaust cam chain replacement much simpler, but no doubt there will be plenty of other things for me to check and empty my wallet onto yet again.

That said - what would be the must-do things to check for, and what can be left alone?  How deep need this particular rabbit hole go...?
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on May 16, 2019, 21:39:28
You pulled this thing apart to fix a stripped spark plug thread?  I just do it while it's all together.  LOL
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 16, 2019, 21:42:00
You pulled this thing apart to fix a stripped spark plug thread?  I just do it while it's all together.  LOL
Yeah, LOL it up mate.  You're not the only one.  ;D

I'd be selling myself short if a stripped thread was indeed the only reason.  I'm also thoroughly curious by nature, and can't leave well enough alone.  I like learning new stuff and getting my hands fucking filthy in the process.  In that regard, I'm not disappointing myself. 
Title: Re: 1982 CB750F... The resto-not
Post by: Popeye SXM on May 16, 2019, 21:42:10
Why not indeed,
Quote
but no doubt there will be plenty of other things for me to check and empty my wallet onto yet again.
ha ha ha, Oh I been there so many times......
Go for it, you only live once.... what is the werst that can happen?, apart from the cut fingers lost money and extreme frustration?
Good luck  :P
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 16, 2019, 21:51:46
.... what is the werst that can happen?, apart from the cut fingers lost money and extreme frustration?
Yeah no that's pretty much the sum of it.  Any or all of the above are almost guaranteed - but if I can get in and out with only one of those things then I'm ok with that  8)
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on May 16, 2019, 22:00:01
I, for one, am glad you pulled it apart and went with a ripping bore.  It's going to be a blast.
Title: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 16, 2019, 22:07:55
And I for two.  There's the right way, the wrong way and the way things happen in my garage.  It's kind of a mash-up of sense, self-doubt, naive enthusiasm and camouflaged creativity. 

And beer. Itís for courage, honest.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 17, 2019, 11:20:24
Call came in from the machine shop - block is bored and honed, fins fixed (I hope).  Will duck out later today and pick the thing up.  Meanwhile, debate is raging over these cam chains.  I'm definitely steering now towards splitting the cases and simply slipping on an endless chain - while I'm in there there are a few other things I can check and replace like the damping rubbers on the primary shaft, a few seals and o rings.  Anything else that is a definite must-do while I'm in there? 

Feel like I'm my own Cousteau - plumbing depths never before explored.  In my garage anyway.  It's the new frontier.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on May 17, 2019, 11:54:50
Tear it down mate. Might as well! All you need is a deadblow mallet and some Yama/Hondabond

(https://media.giphy.com/media/4BgQaxfQfeqys/giphy.gif)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 17, 2019, 11:59:36
Me and Alice.  Totally understand each other.
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on May 17, 2019, 12:06:23
If its your first time getting into a bottom end, what I like to do is draw a rough diagram on cardboard of the bottom case from whatever view you're disassembling it from with an arrow toward the front. I'll punch some holes roughly where the bolts are so its comparable then stick the case bolts right through the cardboard so you don't have to screw around trying to remember which bolt goes where.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 17, 2019, 12:08:22
Good call mate - I do that with all the side covers, oil pan etc.  Dominos boxes are perfect, so that's dinner taken care of too.

Hondabond huh.  Best to go with OEM, right?  Not an off the shelf product?
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on May 17, 2019, 12:33:19
Good call mate - I do that with all the side covers, oil pan etc.  Dominos boxes are perfect, so that's dinner taken care of too.

Hondabond huh.  Best to go with OEM, right?  Not an off the shelf product?

I actually prefer Yamabond its a little cheaper and it stays good for a while. I'm sure you can use something off the shelf but I always just use this stuff. I've had my current tube for a couple years, it hardens up at the end but I just dig it out with a pick and roll on.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 17, 2019, 12:42:55
Had a look online and there are loads of different Yamabonds - would Yamabond 5 be the right one to buy?
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on May 17, 2019, 12:51:07
There's really no difference between Hondabond and Yamabond, chemically.  They're both made by ThreeBond.  You can also get ThreeBond 1184, 1211 and 1207B.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 17, 2019, 12:59:41
Righto, Fortnine (it's a huge website here in Canada) sells ThreeBond 1184 for around $17 CAD so I'll order some of that.  Been looking for an excuse to go shopping there for a while as I need (well, want) another set of Biltwell kung fu grips for the KLR, and a new visor for the lane splitter. 

Looks like I'm splitting the cases then.

"Never get out of the boat.  Absolutely god damn right.  Unless you were going all the way."
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 17, 2019, 13:00:36
Or...

. https://www.youtube.com/watch?v=2GR4Qz3-PNo
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 18, 2019, 21:29:49
Trying to split the cases, everything seemed to be going ok but there's something near the rotor that's putting the serious kibosh on things.  Everywhere else seems fine.  4 hours of wrassling with the thing and I'm stumped. 

The back is clear -

(https://i.imgur.com/gklPVBj.jpg)

the rotor, not so much -

(https://i.imgur.com/W1Rc3kq.jpg)

(https://i.imgur.com/UczfwhD.jpg)

When I lift the lower case up, it brings the rotor (and crank) with it.  Something's stuck.  Any ideas?
Title: Re: 1982 CB750F... The resto-not
Post by: Nybz on May 19, 2019, 04:26:11
Looks like your getting a good schooling on the 1100f.net forum.
Some of them are a bit cranky, but a few of them know this bike inside and out.

Take the god damn rotor off!

What do your main bearings look like?
If they show copper, they are toast.


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 20, 2019, 14:21:44
Indeed - teachers come in all shapes and sizes Nybz.  And it's a fool who thinks otherwise.  I took a bit of a beating over there, but I'm totally ok with that.  The CB1100f forum is a different beast than DTT but no worse off for it.  The guys over there know their onions and no mistake.  They've forgotten more about the SuperSport than I'll ever know.  Amazing help and resource.

So, a productive few days.  Got the newly bored-to-823cc and honed block back, completely with repaired fins, came back mint -

(https://i.imgur.com/1XNZYHw.jpg)

(need to get a photo of the fins, will do today).  Someone over on the other forum mentioned S-100 and pressure washers.  I have the S-100, and just last week my neighbour offered me his washer whenever I needed it.  Penny drop.  Balconies could use a good going over too so made that happen -

(https://i.imgur.com/q7USKzj.jpg)

- then sprayed a load of S-100 and waited 20 mins for it to do it's thing.  Kids, I discovered the coolest way to get totally soaked this summer!  It's easy - line up your air-cooled cylinder block (the more cylinders the better) on a stool at about knee height.  Doesn't matter what engine it comes from, the important take away here is air-cooled.  It's all about the fins you see.  Stand close - really close - and have at it with the pressure washer.  All those fins, nooks and crannies will have you Absolutely Soaked almost immediately.  It's great.  Fun times.

(https://i.imgur.com/CTHZMWU.jpg)

Dammit if the S-100 didn't work a charm though, especially between the cylinders.  Wiped the bores down with some engine oil to prevent flash rust, job done.

After some encouragement and gentle persuasion/peer pressure figured f*ck it let's split the cases.  After the drama of the last post, it became very obvious that the rotor really does need to come off when attempting the job.  Turns out the rear axle of this bike is a perfect fit into the rotor and assumes admirable chops as the pulling tool.  Once I got the rotor bolt out, threaded in the axle and whaled on the thing with a heavy hammer until eventually the rotor popped off -

(https://i.imgur.com/GmZmGNf.jpg)

- and the cases split no pasa nada -

(https://i.imgur.com/W6FNhFd.jpg)

Pulled the main crankshaft bearings, the upper bearings all looked good -

(https://i.imgur.com/REMnR2C.jpg?1)

but the backs of them are showing copper -

(https://i.imgur.com/ZSmMKS4.jpg)

- does that matter?


The lower bearings look ok but two are showing copper -

(https://i.imgur.com/9SQTxO9.jpg?1)

In that case, do I need to replace all the lower bearings? Or just the two showing copper?  They're about $10 each so on the big scheme of things, doable.

The con rod bearings all look good -

(https://i.imgur.com/7q3noar.jpg)
(https://i.imgur.com/bqCdeOU.jpg)
(https://i.imgur.com/qzw3RET.jpg)
(https://i.imgur.com/7r89UXF.jpg)

I'm going to replace the two cam chains, some o-rings and oil seals, I'm not sure about the primary chain, and also want to replace the rubber dampers in the primary shaft.  Anything else I should be on the look out for? 
Title: Re: 1982 CB750F... The resto-not
Post by: wozza on May 20, 2019, 19:54:06
As your down that far Id replace all the bearings and have the crank done as well..copper on the back is normal (AFAIK) as they only plate the running surface..
Nothing worse than spending all that time rebuilding a motor and have a bearing spin a couple of 100 kays/miles down the road.To my eyes those conrod bearing look pretty worn Id also be looking at the oil pump circuit as well ;)
Title: Re: 1982 CB750F... The resto-not
Post by: Popeye SXM on May 20, 2019, 21:22:23
Having gone down the rabbit hole this far... is seems daft (to me at least) not to change all the bearings. All depends of course how long you plan to keep the bike. I do admire your will to make this bike wright, keep up the great work
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 20, 2019, 21:40:44
Cheers gents - I have it on good authority that there's no need to change all the bearings if they're not worn but I can't help agreeing with you, got this far, may as well.  Still, I'd like to learn whether it's a must or not - there are only two lower main bearings that are showing copper, and none of the rod bearings.

Removed the lock bolt on the primary shaft, which involves jamming a flat head screwdriver between the split gear and the crankcase.  Busted a small pry bar but eventually loosed the bolt.  Involves putting the gear back in the case and tightening up a few case bolts to hold it in place, then do your worst -

(https://i.imgur.com/t5XludR.jpg)

With the bolt removed I could then remove a gear and a few washers but came up stuck against the bearing that also needs to be removed.  The Clymers is very vague about this, just says to remove the bearing.  Heat gun?  That thing is jammed on there tight.

(https://i.imgur.com/ipe6wYw.jpg)
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on May 20, 2019, 23:27:29
You'll want to use a bearing puller if you care to reuse that bearing. If you don't have one, you can try freezing that whole assembly, pulling it out of the freezer once its good and cold and hitting the bearing with a torch and the bearing should slide off. 
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on May 21, 2019, 08:00:00
Not much more help on disassembly, but pretty good on the bearings, here is a link to the Honda FSM chapter for this: http://www.cb1100f.net/Other/CB750FManual/Honda1979thru83CB750ServiceManualChapter12CrankshaftPrimaryShaft.pdf

You might need to join the site, but it is free and has great stuff for F bikes.
Title: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 21, 2019, 10:21:34
Thanks man, yeah Iím a member of that forum and I already have the FSM - doesnít really give much info on how to remove the bearing though. The forumís been acting up a little recently but Iíll post my q in there once itís back up and running.

Iíll give AdvCoís suggestion a try - if I apply heat onto the frozen bearing do I run the risk of damaging the bearing in any way? And am I right in guessing that the bearing itself is lubricated by the engine oil, not grease?


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on May 21, 2019, 10:31:51
Iíll give AdvCoís suggestion a try - if I apply heat onto the frozen bearing do I run the risk of damaging the bearing in any way? And am I right in guessing that the bearing itself is lubricated by the engine oil, not grease?

Sent from my iPhone using DO THE TON

Nope, think of it like you're starting a bike in frigid temps. Your cylinders and valves will go from icy cold to hot in short order.

Yes, all the bearings in the engine are lubed by oil.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 21, 2019, 11:09:57
Nope, think of it like you're starting a bike in frigid temps. Your cylinders and valves will go from icy cold to hot in short order.

Yes, all the bearings in the engine are lubed by oil.
Good point.  I don't have a torch per se but the missus has a mini blowtorch she bought for making the sugar go all crispy and fancy on her home made creme brŻlťes.  Unless she makes the things when I'm not around (which would suck), she's never, ever made one and the lighter's sitting on the kitchen shelf unused.  That'll do nicely.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 21, 2019, 19:42:09
Primary shaft's in the freezer, cozying up to some bison burgers and fish fingers - I'll leave it in there overnight and then hit the bearing with the blowtorch over breakfast.  Pretty sure that's what kitchens are for, and if they're not then no doubt I'll find out the hard way.  Again.
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on May 22, 2019, 00:56:25
Primary shaft's in the freezer, cozying up to some bison burgers and fish fingers - I'll leave it in there overnight and then hit the bearing with the blowtorch over breakfast.  Pretty sure that's what kitchens are for, and if they're not then no doubt I'll find out the hard way.  Again.
I officially have never seen this thread....
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 22, 2019, 10:05:19
I officially have never seen this thread....
Then please consider yourself welcomed - officially.




Sent from my iPhone using DO THE TON (http://r.tapatalk.com/byo?rid=89466)
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 22, 2019, 18:09:08
Didn't work - I'll bury it back in the freezer and try again tomorrow.  Guess it's with good reason this bearing is jammed on there so tight.
Title: Re: 1982 CB750F... The resto-not
Post by: pidjones on May 22, 2019, 21:20:09
If you give up and decide on a new bearing (the only reason I'd take it off), you could remove it like we do the headstock lower inner race. Cut the outer race and ball cage off with a rotary tool and cutting wheel. Then carefully cut most of the way through the inner race and smack the slot with a cold chisel or fat screwdriver.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on May 22, 2019, 21:26:15
Thereís a good reason for removing the bearing as Iíve recently learnt. Behind it is a housing that contains small, segmented rubber dampers. These can/do wear down - replacing them with new rubber allows for smoother operation of the primary chain and eliminates any chain rattle. Assuming of course that your primary chain is in good condition.


Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jun 13, 2019, 12:06:39
Damn it's been a while.  In the end, won ugly.  Had the thing sitting in the freezer for about two weeks - not entirely because I wanted to get it really, really cold but more so because I forgot all about it.  Life/work/summer(ish) getting in the way and that.  Had at it with a bench vise and big chisel and pried the damn thing off.  Bearing still spins cleanly, and with it removed I could finally get at the once-rubber dampers in the primary gear housing -

(https://i.imgur.com/XTfQ3xv.jpg)

Good thing too, one of them looked all chewed up -

(https://i.imgur.com/kkP24tJ.jpg)

- and all of them were completely plasticized and cracked -

(https://i.imgur.com/V7M9FIt.jpg)

OEM originals are rare as pope shit but there's a guy over on cb1100f.net who makes perfect replicas.  That'll do me.

I need to switch out some of the lower case main bearings (2 really) as they're showing copper - I'll replace all 5.  Not the upper main bearings though (good plan?) as they look fine.  All the colours have worn off the bearings themselves so that's that out the window, and I'm a little unsure as to where to look for the inked markings on the crank.  Would the inked markings be on the 5 silver coloured parts of the crank (the part that sits in the bearings), or on the lobes?  I can't see diddly.

(https://i.imgur.com/eVsLzTx.jpg)

I do however have it on good authority that replacing the bearings with the loosest replacements (in this case, bearings with a yellow marking) will work just fine - better looser than tighter.  Also, the difference between the different coloured bearings is really fractional apparently, so replacing all 5 lower main bearings with yellows should - I'm assured - be fine.  Anyone done this?
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jun 14, 2019, 13:07:09
Learned that the letters (on this engine, BBBBB) stamped into the case refers to the size of the crankshaft bore(s) through the cases.  As the letters are all the same, this means that each of the 5 bore holes are the same size.  The letters are either A, B or C - these letters are then cross-referenced against (long washed off) inked-stamped letters on the crank lobes to determine what size (colour) main bearing shells to use. 

As I need to replace two lower main bearing shells - but the colour markings on both of them has been erased - I'm thinking that, as a couple of the other bearings still have brown markings, that I can replace the worn bearings with brown too.  Again, I'm assuming this because of the BBBBB stamps in the case - indicating that the bores are all the same size.  Bueno?
Title: Re: 1982 CB750F... The resto-not
Post by: CrabsAndCylinders on Jun 14, 2019, 20:47:28
You're learning the ABC's of engine rebuilding!

Sorry about that.
Title: Re: 1982 CB750F... The resto-not
Post by: Nybz on Jun 14, 2019, 22:21:36
It is a bit confusing in the Honda manual, but yeah you have to cross reference those stamped marks on the case with the ink stamp on the crank. (Which by now is probably invisible by now)
I think it would be a safe bet just to get yellows...I could see the colour on the sides of my shells. So I just replaced those with the same.




Sent from my iPhone using DO THE TON
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Jun 15, 2019, 00:40:27
They have a corresponding measurement and service limit. You have to measure them and see what you need, then get the color based on your measurement. Each color has a .005 range.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jul 15, 2019, 19:33:00
As anyone who's ever painted an engine knows (and as I'm finding out the hard way), preparation is nine-tenths of the chore...

(https://i.imgur.com/d707hox.jpg)
(https://i.imgur.com/j7SOvtq.jpg)
(https://i.imgur.com/TSSdVw1.jpg)

But after (sporadic) months, it's starting to look like something.  No internals at this point, just a mock-up -

(https://i.imgur.com/QtYMZyR.jpg)
(https://i.imgur.com/0P4IS0o.jpg)
(https://i.imgur.com/EpajxvJ.jpg)

Side covers still need deciding on, but liking how it's looking.  I used DupliColor low gloss black engine enamel and polished some details on the cases.

Now to take everything apart and make the thing work.  How hard can that be... 
Title: Re: 1982 CB750F... The resto-not
Post by: irk miller on Jul 15, 2019, 19:55:21
I do not paint engines.  I just clean them and make them run well.  LOL
Title: Re: 1982 CB750F... The resto-not
Post by: trek97 on Jul 15, 2019, 21:29:57
Thats some crazy masking.

I just loosely half ass em all together w minimal bolts, (1 or 2 per cover)

Spray, let dry, disassemble, wipe paint off off un-painted parts w cleaner.  done

Title: Re: 1982 CB750F... The resto-not
Post by: trek97 on Jul 15, 2019, 23:35:42
Super work.  It looks nice   8)
Title: Re: 1982 CB750F... The resto-not
Post by: advCo on Jul 15, 2019, 23:38:19
That sure is pretty.


I'm going to buy stock in green masking tape.
Title: Re: 1982 CB750F... The resto-not
Post by: Maritime on Jul 16, 2019, 08:33:20
Damn nice work Jim.
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jul 16, 2019, 10:53:46
Cheers gents, work on this bike has been pretty geologically slow since the summer started but thankfully I'm in no hurry to get it done.  Which is a good thing - hit the year-in mark and still looking at a pile of parts  8) 
Title: Re: 1982 CB750F... The resto-not
Post by: cb250nproject on Jul 19, 2019, 07:57:28
Can't rush perfection, you can't force it either I've tried to do both and failed
Title: Re: 1982 CB750F... The resto-not
Post by: Jimbonaut on Jul 19, 2019, 22:41:29
Got the rest of the side covers etc painted, and a few details more details polished up as well.  And, as I have zero restraint, couldn't help buttoning it all up (minus internals) with some new shiny hardware -

(https://i.imgur.com/KculIWy.jpg)

(https://i.imgur.com/w4p7oM7.jpg)

Few more details to finish up but it's almost done.  Now that I've replaced all the old hardware with new stainless bolts, I'm on the lookout for a set of new stainless upper and lower crankcase bolts as well. Anyone know where I can get some? They absolutely don't need to be OEM.

Have some new cam chains in the mail. Also arriving soon are a set of yellow crank bearings, oil seals and primary shaft dampeners. Then the fun begins.
Title: Re: 1982 CB750F... The resto-not
Post by: doc_rot on Jul 20, 2019, 03:50:22
Looks great. I mask my engines the same way,its worth the results.
Title: Re: 1982 CB750F... The resto-not
Post by: trek97 on Jul 20, 2019, 07:19:50
Gorgeous