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Blood Sweat Tears and Grease => Engines => Topic started by: Sderbyshire on Jun 01, 2018, 04:34:19

Title: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 01, 2018, 04:34:19
Hi everyone, iím back after a period away from messing with my 360.

Have an oil weep from the head to barrels join, both sides, so am going to strip the top end down and potentially bore and install gs850 pistons.

Looking on ebay there are new aftermarket pistons available, or old engines.

Which should i go for as i think NOS are pretty rare these days?

Iím competent with a spanner but havent rebuilt an engine before, so want to keep this simple......

From reading threads on here and hondatwins i think i need to bore the barrels, and deck the pistons by adding a copper base gasket of the appropriate thickness?

Anything else essential?

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 03, 2018, 12:36:45
Took a break from decorating to tear down the 360 motor!

All went very well, no problems at all.

Previously iíve only uad the rocker box off but judging by the red Ďgasket sealerí on the base gasket someone has been here before?

So now i need to source a pair of gs850 piston sets and then have the barrels opened up to suit.

I want to keep this simple so am not changeing anything unless i need to, any suggestions as to what extra work is essential/worthwhile while i have the top end in bits?

Steve
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jun 03, 2018, 13:42:10
You'll need a new head gasket for the larger bore, I recommend solid copper for head and base, better heat transfer. You'll need to get bore done first so you can check clearances to order correct thicknesses to get around 0.040" piston to head clearance
You WILL need heavy duty clutch springs with bigger motor, they are barely adequate for stock engineIt's a REALLY good idea to do various oil system modifications, need clutch and generator cover gaskets as covers have to come off.
 If you havcent looked through Miniature Ninja's build you should, he's got pictures of various mods and it will beeasier than looking through my 360 build/blog to find the informationWhen it's all done you can treat it as a very reliable high rpm Triumph 500, will be about same size, weight and power output but with an extra couple of gears and a higher cruising speed (80mph is generally no problem)As for after-market or used, doesn't really matter as bore should be matched to piston size, use 0.0015"~0.0017" piston to cylinder clearance
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 03, 2018, 13:53:48
I've recently "completed" my 378 build, although I have yet to fire it up pending finishing the wiring. Last week of School for the kiddos has been holding things up for me.

notes and comments:
I ordered custom copper head and base gaskets from coppergaskets.us  (https://coppergaskets.us/shop?olsPage=products%2Fhonda-cb360-copper-head-gasket-69mm-x-042-106mm-thick)as PJ said you need to have the new pistons in the bored out cylinders to measure how far up they stick out so you can get gaskets made in the correct thickness. so steps: 1- buy pistons 2- have cylinders bored out to match pistons with proper piston/cylinder clearances 3- install and measure deck height 4- order gaskets 5- put it all back together again (dont worry, you will do this about 10 times before it's all done)

my build has some other complications as I have also gone the route of larger valves and some other things - but suffice to say that while you've got the engine apart it's more than worth it to take care of some of the oil passages that plague these engines, that will add some time and effort to the build but absolutely worth it and most likely necessary too.

any reason you took down the motor?
there are things that should be done to it - like tensioner replacement, filter cleaning.
my engine was as clean as a whistle inside and by doing a "simple tear down" I ended up doing everything in the book to this motor! LOL it's an addiction
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 03, 2018, 14:49:43
Thanks both for the constructive replies.

Iíll look into the oil mods and make those, filter cleaned out not long ago.

Iíll also read minatureninjaís blog, as iím unsure exactly how to calcilate what base gasket thickness iíll need. Will then buy copper as recommended.

Thanks again!

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 08, 2018, 10:24:33
Hi all

Awaiting delivery of a pair of aftermarket gs850 pistons from Japan...... so tore the head apart and opend out the exhaust ports to more closely match the ex gaskets.

Couple of pics attached.

When the pistons arrive iíll have the barrels bored out to suit, i went for 70mm pistons.

Meantime iíll read up on the oil mods and get those done ready for reassembly, 10 times !

Steve
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jun 08, 2018, 11:11:53
Should be interesting. Doesn't 70mm give you a 391?
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 09, 2018, 04:40:21
Iíve had a search but struggling to find the 360 oil system mod info.

Could someone point me in the right direction please?

Thanks

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 09, 2018, 06:22:29
Is this the oil mod that i need to do to improve oil flow to the head?

Seems to be a very small opening out of the edges of the transfer piece, just removing the Ďstepí ??

Steve
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 09, 2018, 16:01:36
Is this the oil mod that i need to do to improve oil flow to the head?

Seems to be a very small opening out of the edges of the transfer piece, just removing the Ďstepí ??

Steve
Yup, that's the way I did mine (well duh, that's my photo) but also the way PJ had done his. Basically you're just removing some of the restriction this bypass part has, allowing more oil through the ports and less dumped out the bypass.
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jun 09, 2018, 16:18:59
You'll want to open these ports 1/32' more...

(http://i1086.photobucket.com/albums/j449/trek97/oilhole.jpg)

Then the clutch basket...

(http://i1086.photobucket.com/albums/j449/trek97/clutchmod1-1.jpg)

And try to find a CJ pickup.  Although, you can get away without a CJ pickup with good oil level maintenance and limited side stand idling.

All those pics are photobucket, which means they may not be showing up unless you have the fixer extension.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 09, 2018, 17:49:04
Thanks both!

Iíll dremel the bypass as per your photo Minatureninja.

Irk, what size holes are you suggesting i drill in the clutch basket?
And what sise is Ďopening out by 1/32í , do i drill that or file it bigger??

Thanks again

Steve
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jun 09, 2018, 19:23:32
They're the oil passages bringing oil to the top end.  I can't remember exactly what size the holes are now, but you're just making them slightly bigger- 1mm or 1/32" bigger. 
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 09, 2018, 19:28:42
Thanks both!

Iíll dremel the bypass as per your photo Minatureninja.

Irk, what size holes are you suggesting i drill in the clutch basket?
And what sise is Ďopening out by 1/32í , do i drill that or file it bigger??

Thanks again

Steve
I drilled the headbolt oil holes out to 3/32 and used either a 9/64 or 5/32 bit for the clutch basket (basically just what fit between the splines)

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Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 09, 2018, 21:29:15
Thanks MinatureNinja

Whats the point of the clutch basket drillings?

The pther two mods allow more oil flow to the head, but i dont see what the clutch basket holes do?

Steve
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jun 09, 2018, 21:38:39
That and the HD clutch springs help clutch performance, especially with the bore. 
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 09, 2018, 23:32:25
as Irk said, it improves performance

it does this because it allows the oil in the clutch to flow out of the plates at RPM when the clutch is disengaged and run much cooler. cooler oil = better performance overall
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jun 10, 2018, 00:26:33
It makes clutch run cooler. Oil flows through the plates all the time engine is running, (it's a 'wet' clutch) this mod directs more.  oil through the center plates so they are less likely to overheat. When you pull clutch in plates disengage and oil flushes any 'dust' It's used on 200+bhp bikes so it must do some good  ;D (although I've been doing mod since 1970's, kinda sucked trying to explain it to 'experienced' mechanics)
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 10, 2018, 04:31:41
Excellent, thanks guys.

I understand about the clutch being cooled by the oil, although iím more of a Ducati dry clutch man really!

HD springs ordered and iíll get my drills out :-)

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 10, 2018, 04:47:31
Ps, also ordered a CJ360 pickup on ebay.

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 12, 2018, 04:21:19
70mm pistons arrived from Japan in less than a week!

Off to the machine shop today 😎
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 12, 2018, 20:22:02
Ps, also ordered a CJ360 pickup on ebay.

Steve
WHAT?!?!?! I've been scouring the Ebay for months for one of those!! :(
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jun 12, 2018, 20:25:52
WHAT?!?!?! I've been scouring the Ebay for months for one of those!! :(

As annoying as it is, you have to get them as soon as they post.  I got mine within 20 minutes of the listing being posted.
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jun 12, 2018, 22:46:59
They never stopped CJ cam bearings failing so it's only needed if you don't ever check oil level plus park on side stand on highly cambered roads and leave bike idling for extended period. It would probably be easier to weld over the original pick up and extend it into center of case or even just make a complete new pick up?
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 13, 2018, 00:44:56
They never stopped CJ cam bearings failing so it's only needed if you don't ever check oil level plus park on side stand on highly cambered roads and leave bike idling for extended period. It would probably be easier to weld over the original pick up and extend it into center of case or even just make a complete new pick up?

I have a spare CB pickup, so I may take that up and make a modified one. I am meticulous about checking proper level and change intervals because I know how important that is to engine life for anything (plus being a former Marine has taught me that equipment maintenance is key to survival)
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 13, 2018, 03:35:24
Iím a little jubious that the pickup will be genuine CJ..... lets see what turns up!

Meantime iíve done the oil mods, and taken the pistons and barells to the shop 😀

Also contacted CopperGaskets to line them up for base and head.

Iím awaiting a gasket kit and viton valve seals, the ones in the old kit i have seem crap, then i think iím ready to assemble.

Will post pics when stuff arrives.

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 14, 2018, 11:36:11
Well the ĎNOS CJ360 Oil Pickupí arrived, and yes itís genuinely not the same as the CB360 one, and looking unised and a bit rusty!

I shall clean it up and install.

With the pressure relief mod, clean oil pump, drilled clutch basket and oil ways drilled out to 2.5mm ( they were 2mm) i think im ready to button up the right case?

Steve
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 15, 2018, 14:50:42
Sounds like it, you got the heavy duty clutch springs in there?

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Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 16, 2018, 10:10:14
Yes, hd springs installed.

Ps, thereís another cj360 pickup listed on abay by the same seller.....

Steve
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 16, 2018, 15:20:28
Yes, hd springs installed.

Ps, thereís another cj360 pickup listed on abay by the same seller.....

Steve
Cool thanks.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 20, 2018, 08:52:00
Collected barrels and pistons from the machine shop this morning, and so couldnt wait to test fit and measure up for gaskets!

With a new base gasket in place and the barrels bolted down iím seeing :

Pistons sticking up .045 from the barrels
Base gasket measuring 0.018

So if i went for a base gasket at 0.063 from Lani then iíd have pistons perfectly flush with the barrels.

A 0.042 head gasket would then give me clearance of 0.42.

Is this correct and the right approach?

Steve



Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jun 20, 2018, 09:10:13
Yep.  That's the way to do it.
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jun 20, 2018, 11:16:08
Yep, numbers work out
Did you check gasket after it was compressed? I doubt if it would be more than 0.001" but it's generally easier to clamp cylinder down without gaskets then work out what combination will get you closest to 0.040" clearance. Having thickest gasket on base is a real good idea as there is way less pressure 'down there'.  ;D I'm really interested to see how a 70mm bore turns out. When I did my CJ250 to 70mm I used GS1000 pistons and flycut the head. Using stock 360 head gives a different combustion chamber shape and probably volume? I was actually on TV with it in 1995 (or 6?) There was an event at LLandow  Circuit with a RWYB 'sprint' Thanks to the 'magic' of television, I was filmed during a run then it was cut into the Welsh Champion drag racer doing a huge wheelie off the line making it look like I was 'winning (even though filmed on different days) only another 14 mins, 55sec to get my full '15 minutes of fame'  ;D
 
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 20, 2018, 11:24:33
Thanks both.

I did measure base gasket after removing it, so had been compressed.

Iíll order the copper gaskets and hopefully get rebuilding soon!

Iím a little unsure on piston rings.

I have a three part oil control ring, being two thin rings and a Ďwavyí centre, and two thicker compression rings.
Both compression rings are stamped Ď100í on what i think is their upper face. One ring is black edged and one silver.

Have you seen this before?, iíve not take a picture yet nor contacted the seller.

Steve
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jun 20, 2018, 11:29:18
Rings are completely normal, marked as 1.00mm oversize. Expander ring goes in between side rails. Make sure ends are butted and not overlapping (sometimes they look 'too tight' assembled correctly) Side rsails don't haver up or down face
Top ring is chrome face, second ring is 'black'
 Numbers up.
 Oh, stagger the oil ring rails and have gaps 'opposite' the 'join' on expander,(I only go about 1/2" either way)  it only makes a tiny difference but can seal 'better'.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 20, 2018, 12:01:20
Fantastic, thanks CrazyPJ!
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 23, 2018, 06:10:30
Gaskets ordered from Lani at Coppergaskets, he was very prompt in responding and in making and posting the gaskets too!

While i wait for those to arrive iíve painted the head and barrels, and built the head back up with new Viton seals.

Cant wait for the gaskets to arrive so i can rebuild and fire up the CB389 😀
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 23, 2018, 14:06:00
Moving right along there. I had quite a bit less meat on my build, and that's what I did went with a thicker base gasket. You could probably get away with shaving some off the case but gaskets is more reasonable solution.
Factory valves and guides?

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Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jun 23, 2018, 15:34:15
Stock valve guides are actually real good. It's only if you fit oversize stainless valves the guides need changing (something they don't tell you when you buy stainless steel valves, the stemscan  gall in cast iron and need bronze guides) Really though, it isn't worth the extra expense of oversize exhaust valves but the+1 (35mm) intakes will make all the port work better as it's already oversize.With a '390' is should be good to 'cruise' around 85~90 with top end around 120 on stock gearing (17/34) I got confused the other day with the CB550 591cc 'kit' and 70mm 389.46cc of 360 (35x35x3.14159x50.6x2 = 389.4629)
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 30, 2018, 04:05:01
Gaskets and new dowells arrived in the week so guess what iím doing this weekend 😎
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jun 30, 2018, 12:34:15
Pj, I've used stainless valves on cast guides for years in automotive application. The KPMI valves are microscopically coated anyway, should not need bronze guides according to their tech qa https://www.kpmi.us/tech-support---faq.html

I did in fact call them and they assured me the factory guides in cb350s and cb360s have been used successfully.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jun 30, 2018, 13:58:44
So, rebuilt the engine, fitted the ancilliaries and it fired right up!

But only running on one cylinder.

Right cylinder not contributing to the fun and spark plug seems to be dry so probably a fuel issue.

Iíll investigate tomorrow.

Pics, and video!, to follow shortly :-)

Steve
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jun 30, 2018, 16:17:58
Great to hear it's a runner.. Use stock Kei-Hin pilot jets instead of aftermarket kit ones. Set float height to 21mm. CJ carbs are exactly the same as late CB (I brought a set back last time I was 'home')
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 01, 2018, 05:43:21
Up early and re timed the ignition, as wasnt confident it was correct, and we have success!

A quick spin around the block indicates a beefier sound and strong pull at low revs, and clutch slip as soon as the motor get to about 7k. Which is disappointing as i did fit Ďheavy dutyí clutch springs. Sourced on ebay so maybe crap.

I wonder if i need new friction plates as well as hd springs?

Whereís a good source for springs and plates guys ?

Iím very happy the bike is running properly as this was my first engine rebuild, albeit only the top end.

Hereís a pic of the CB389 resting after its first run.
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jul 01, 2018, 14:32:31
I only use Bore-Tec springs for 'race' 350's. Were they thicker wire and slightly shorter than stock Honda? EBC do a set but I haven't tried them. Stock plates are probably better than anything else Barnett tend to 'grab' a bit but are a lot better than 30+ yrs ago when they were 'drag race only' Glad you have a very noticeable difference in performance, it's even better when clutch stopps slipping as you have at least another 3K to go  8) 8)
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 01, 2018, 15:44:50
Hi PJ

The Ďheavy dutyí springs are longer than standard and seem to be the same thickness/strength.

Iíll look out some of the ones you recommend.

What do you think of EBC clutch plates?

Really looking forward to giving the new motor a good blast once the clutch is fixed!

Steve
Title: Re: Possibly entering the 378 club!
Post by: trek97 on Jul 01, 2018, 17:35:42
Bore-tech is closing the doors, due to health issues.  so when they're gone - they're gone.

I was glad to see they still had the springs available when I ordered them for Piglet, I ordered an extra pair just to have on the shelf for any future bikes.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 01, 2018, 18:28:20
Had a search and found the bore-tech site.

Springs very reasonably priced but shipping quoted at $55 which is a bit silly.

Guess iíll try ebc!

Steve

Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jul 01, 2018, 18:58:17
USPS went nuts a couple of years ago so shipping is crazy for anything outside USA. Medium flat rate box used to be around $27.50, last time I looked it was $48.00 to Britain. Even sending stuff to Canada more than doubled. Even so, $55.00 is way OTT as about 6 sets of clutch springs would fit in a small flat rate box and that should only be around $20.00 or less.If you could find a few more people who wanted them you could have them sent to me and I could re-post to you with Customs Declaration, I doubt a single set would be cost effective?
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jul 01, 2018, 19:26:37
I ship all over the US and world with parts I make and sell.  I don't get hit with shipping like that at all.  I just shipped some parts (rubber plugs) to Australia for $13.54. First Class International. 
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 02, 2018, 09:13:16
An update, one step forwards and two back !

Dubious of the Ďhdí springs i whipped them out this morning and compared with the std springs. Wire thickness on the Ďhdí springs is thinner than the std springs, no wonder the clutch slips!

So back in with the old springs and out for short test ride, very short....... as the engine seems a little rattly then stops suddenly.

Took out plugs and span motor over, valvs not opening so off with the rocker cover and I find the timing chain is off the sprocket, which is broken and the bolts are out.

Iím sure i tightened the bolts but obviously not as it looks like one undid, then the sprocket wobbled and ripped out the other bolt and destroyed itself.

Iím assuming it will have bent a valve in the process, not had head off yet.

Iíll obviously need a new sprocket, and probably the cam too as one thread looks knackered, or could helicoil it?

Thoughts?

Steve
Title: Re: Possibly entering the 378 club!
Post by: advCo on Jul 02, 2018, 09:31:04
That's a bummer. I always use Loc-tite on those cam sprocket bolts just in case.

You could helicoil or tap to the next size up, although I don't know if swapping up to a larger bolt (added weight?) would affect the balance of the cam while its spinning at speed...could be negligible ?
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 02, 2018, 10:46:53
Took a closer look at the cam and the threads are ok, one is perfect and the other cleaned out ok with an m7*1 tap ( was surprised it was m7)

So i may get away with a new sprocked and pair of bolts, any suggestions as to where to source those ? (Sprockets common on ebay in us but not sure for bolts)

I remove the head later and assess valve damage ......
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jul 02, 2018, 12:53:01
Get new bolts from Honda, pretty sure they still use them on various motors but you'll need a parts guy who knows how to look up superceded numbers (probably a lot of them?)
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 02, 2018, 13:01:55
Thanks PJ

Iíve found a source of bolts here in the uk, cam sprocket too but cheaper to have it shipped from the us!

I have two bent exhaust valves, one slightly and one very bent !

Inlets look ok, no marks on the valves or pistons.

Is this what youíd expect 360 experts??

Iím regretting not double chcking those cam sprocket bolts !

Steve
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jul 02, 2018, 13:28:18
Checking wouldn't have mattered if you over-tightened the screws.  Over-stretching from over-tightening will also cause failure- either breaking or loosening.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 02, 2018, 13:36:17
In all honesty iím not sure i went back to the first b9lt at all, after rotating the cam to fit the second !

New valves ordered very cheaply from isreal...... wonder if theyíll turn up!

Watch out for the next episode in ĎSteveís first engine rebuildí :-)

Steve
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jul 02, 2018, 17:56:35
this is precisely the thing that scares the crap out of me when building an engine

sure I was able to do my CB360 myself.... but hitting that starter button for the first time was a little nerve wracking
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jul 03, 2018, 10:44:07
More than once I've re-stripped top ends to check cam bolts. So far, I've always had them tight but it's so 'automatic' to me I forget I've done it. I don't think it's possible to over-tighten those bolts? I use a long 1/4" drive extension and 6 point socket. so I can get 'outside' head.  Never yet had one come loose (yet). It is likely you 'got excited' and only did them finger tight? It's more normal for exhausts to bend, they can get tangled with intakes and pistons., they close 'later' as things start going wrong You need to pull intakes to check them, just in case there are any marks on edges. Is there damage on head/cam bearings where bolts backed out? Generally eay enough to filer off any burrs (I fixed a lot of CB/CJ250's before UK had 125 learner law)
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 03, 2018, 10:58:56
Thanks PJ

I may indeed have not tightened at least one of them up properly!

Thanks for the tip on intakes, thay look unmarked and were watertight when i cleaned the head in the parts washer to clear out any metal fragments, but i guess i should remove them to check edges.

Am now awaiting a sprocket amd bolts from the US and two exhaust valves from Israel, wonder which well get here first ( prob the sprocket as thats no use until i have the valves!)

Its all a fun learning exercise, lucky i have a few other vehicles :-)

Steve
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jul 03, 2018, 11:13:38
Check valve tips are hard when you get them, guy over on Honda Twins has had 2 sets of intakes 'pocket' and break. Hasn't had issues with exhausts but still worth checking (just use an old file, if it cuts they are 'soft') I've never seen anything like it and without access to running motor can't be a lot of help as there is always a possibility her's doing something wrong?
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 04, 2018, 07:55:21
Thanks for the valve tip PJ, will check when they arrive

In the meantime iím thinking i should replace the chain tensioner, but i cannot remove it.

The spring loaded arm moves ok, can push it down with a big screwdriver and it springs back up smoothly.

But i cannot pull the tensioner out of the socket in the sprung arm. Photo attached shows what looks like a thread inside the curved end of the tensioner, is it bolted in place ?

Has anyone seen this before?

If it is bolted in place then iíll have to split the cases if i want to renew the tensioner, how hard is this, looks simple in the manual?
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jul 04, 2018, 08:53:49
It's bolted in place.  Looks like this:

Top part in the pic.
(http://www.hondatwins.net/forums/attachments/130610d1483572772-cb360-cam-chain-tensioner-holder-img_2821.jpg)

Your tensioner is in backwards, which is why it's hanging up.

Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 04, 2018, 09:12:05
Thanks Irk, but the issue is at the bottom of the tensioner not the top.

Your picture is of the top fastener, mine was taken down the oblong chain hole of the bottom fixing.

From the exploded diagram ( attached) my challenge is getting the tensioner out of the end of the swing arm ( part 10/15)

In my photo there appears to be a thread inside part 10, through the loop in the end of the tensioner, thus preventing it lifting out??
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jul 04, 2018, 09:26:05
That pic of yours is sort of confusing.  What I think I'm looking at in the pic is part 15 in part 10, with the tensioner (part 1) removed.  Is this not correct?
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 04, 2018, 09:40:48
Yes, You are looking at part 15 in part 10, but part 1 is stuck in and wont lift out.

You can see the tail of the loop on the bottom of part 1, and below that is what looks like a thread.

My problem is that part 1 will not lift out, i have pulled quite hard.....
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jul 04, 2018, 16:55:15
Is that not the broke cam gear bolt stuck in the tensioner arm?

I fear you are going to have to split the case to resolve that.
If you need a spare tensioner arm I have a few.
Title: Re: Possibly entering the 378 club!
Post by: trek97 on Jul 04, 2018, 18:12:22
That pic you posted is confusing as all get out. 

It looks to me like someone has drilled the cup #10 and ran a bolt through the eye in bottom of the tensioner slide blade.

And also the tab on part #15 is bent downwards rather than up. 

Its just weird looking all around.
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jul 04, 2018, 18:29:17
I wonder if MiniatureNinja called it.  The cam gear bolt.  It makes sense that the chain dragged it down into the tensioner holder and just pounded it in place.  Regardless, the tensioner is really hard to figure out by that pic.  I'm not seeing the tensioner at all.
Title: Re: Possibly entering the 378 club!
Post by: trek97 on Jul 04, 2018, 18:35:02
and BTW, what brand heavy duty clutch springs did you buy,  that were lighter wire than the stock springs?   :o

So, I can avoid buying those myself, later in life. 
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jul 04, 2018, 19:08:37
That pic you posted is confusing as all get out. 

It looks to me like someone has drilled the cup #10 and ran a bolt through the eye in bottom of the tensioner slide blade.

And also the tab on part #15 is bent downwards rather than up. 

Its just weird looking all around.

that was my thinking but I dont know why the hell someone would do that, or how they would get it back together properly once done - looks like the left side there is a head there but it would rub on the case?
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 04, 2018, 19:21:45
Thanks for the comments.

I think it is a bolt that someone has tapped into no10 to Ďsecureí the tensioner through its eye, i agree you can see a slim bolt head in the pics.
Its not the cam sprocket bolts as i have them, and the tensioner would not pull out before my mishap with the sprocket

The clutch springs were Ďwalkerí brand from NZ, avoid those!

So.... how much of a job is it to split the cases?
Looks like both side covers off, engine out, undo all the bolts?

Are there any complexities?, iíd hate to have bolts shear or other unforseen problems but think i need to get to the bottom of the cam tensioner.

Title: Re: Possibly entering the 378 club!
Post by: trek97 on Jul 04, 2018, 21:29:42
Its really no big deal to split the cases.  Pull all the bolts.

Flip it upside down.  Pull out the bolts on bottom,  Remove bottom case. 

Flip it rightside up.  As you pull the transmission parts from upside down top case.  Flip em and drop em right back in bottom case. 

That way you wont get anything confused and turned around.

I didn't bother disassembling or removing kick start shaft from the top case.  It will just stay where it needs to be.

If I recall I don't think I had to pull the rotor off the crank either.  But the oil cup probably needs to come off.  Its been a long time since I did it.

take good pics of the gear shift stuff around and behind the clutch basket. 

 
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jul 04, 2018, 23:13:31
Shouldn't you be able to leave the guts in the upside down top half of the case and just pull the bottom off and then when you fix the tensioner arm, put it back on and bolt together?
Title: Re: Possibly entering the 378 club!
Post by: trek97 on Jul 05, 2018, 08:36:44
hmmm. I don't see why you couldn't do that.

But, its been a long time since I opened mine.
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jul 05, 2018, 09:41:24
Yes


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Title: Re: Possibly entering the 378 club!
Post by: Bone91 on Jul 05, 2018, 10:02:56
Is that not the broke cam gear bolt stuck in the tensioner arm?

I fear you are going to have to split the case to resolve that.
If you need a spare tensioner arm I have a few.
Hey MiniatureNinja, you wouldnt happen to have a spare cam chain guide i could purchase off you?

Sent from my SM-G930F using DO THE TON mobile app (http://r.tapatalk.com/byo?rid=89466)

Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 05, 2018, 12:01:49
Shouldn't you be able to leave the guts in the upside down top half of the case and just pull the bottom off and then when you fix the tensioner arm, put it back on and bolt together?

This will be my approach, minimise disruption and chance of putting it back together incorrectly!

Whatís the liklihood of case bolts breaking when i undo them?
Should i reuse old bolts or buy new?
Anything else to worry about?

Steve
Title: Re: Possibly entering the 378 club!
Post by: advCo on Jul 05, 2018, 12:20:48
This will be my approach, minimise disruption and chance of putting it back together incorrectly!

Whatís the liklihood of case bolts breaking when i undo them?
Should i reuse old bolts or buy new?
Anything else to worry about?

Steve

No reason they would break. I use a piece of cardboard and draw a basic outline of the cases as you're looking at it upside down, punch some holes and stick the bolts in so you know where they all go on reassembly.

You will want to take care as there are some retainer pins in a few of the journals that may come with the bottom end and have the possibility to fall out.
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jul 05, 2018, 22:45:56
Unfortunately I do not have a spare guide, the ones I replaced in my current project were original and terrible. I bought the upgrade set from sparkmoto
Title: Re: Possibly entering the 378 club!
Post by: Brodie on Jul 06, 2018, 00:01:58
http://www.sparckmoto.com/Products/Detail/56
Title: Re: Possibly entering the 378 club!
Post by: Bone91 on Jul 06, 2018, 02:40:20
Ahhh too easy Miniatureninja and thank you for the link Brodie

Sent from my SM-G930F using DO THE TON mobile app (http://r.tapatalk.com/byo?rid=89466)

Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jul 06, 2018, 02:53:27
This will be my approach, minimise disruption and chance of putting it back together incorrectly!

Whatís the liklihood of case bolts breaking when i undo them?
Should i reuse old bolts or buy new?
Anything else to worry about?

Steve

there was a thread (a very detailed thread) on the hondatwins site back in 2012 or so, never finished and the guy disappeared but he broke several of those case bolts, I would be prepared for it and take it slow, considering that is must have been done in the past - since someone put a bolt in the tensioner arm, I would say be on the lookout for other things inside that may be improperly installed or missing
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 08, 2018, 08:55:07
So, valves arrived yesterday, from israel in 5 days !!!

Still awaitng the cam sprocket and bolts.

Iíve decided that although the cam tensioner is clearly Ďmodifiedí it has been working fine for the 3 years iíve had the bike so am going to put off separating the crankcases and get the motor running.

I want to see how itís working in 389cc configuration and then address any issues at the same time as the tensioner over the winter. There have been several bodges on this bike that have come to light during my ownership, so to be honest i dont want to uncover anything else in the crankcase unless i have to !

Watch out for updates when the sprocket and bolts arrive, hopefully this week.

Steve
Ps, shall be loctiting and tripple checking those pesky 7mm bolts !
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jul 08, 2018, 20:26:09
I never loctited mine and I'm just crossing my fingers everything inside there doesn't explode.

I already got a scare when I left the points advancer/cam bolt off and the bike jumped ignition timing, back-firing loudly before dying the very first time I started it up...
hope that is all the scare for my bike!

as for opening up cans of worms - yea save it for the winter!
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jul 09, 2018, 16:37:58
Case bolts should come out pretty easy. Never had a problem re-using them. It may be a good idea to get a flat punch and 'shock' them with a sharp smack before trying to unscrew though. I've done full stip, all mods, new cam chain and tensioner 'horseshoe' in about 10 hrs (from bad runner to good runner, engine in and out etc) Not sure if I could do it as fast today though as arm and back are pretty messed up plus I'm 10 yrs older  ;D
Title: Re: Possibly entering the 378 club!
Post by: advCo on Jul 10, 2018, 12:13:14
Pretty sure I use a couple of taps with an electric impact to break them loose on both the CB360 (I had to split the cases like 3 times on that bike  ;D) and the XL, haven't broken one yet.

The small taps are better than a breaker bar with a lot of leverage IMO with those long collared case bolts. In any case they aren't torqued very high so they shouldn't take that much force to break loose.

That being said if you haven't had any issues with the tensioner I wouldn't even bother messing with it.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 14, 2018, 13:58:39
In the absence of engine parts, seem to be coming from the us to the uk by donkey...... i thought iíd tidy up the tail end and do some badge engineering :-)

The 70mm pistons equate to a displacement of 389.4cc which is pretty close to 390cc..... and a 9 is an upside down 6.......

Careful work with hacksaw and dremel and we have a CB390 !

Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 14, 2018, 14:00:26
Arty garden shot......
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jul 14, 2018, 14:28:20
How cool is that! I have thought about modifying the cylinder badge by making it say "376" but thats ok... I'll stick to explaining (bragging) that it's really a 380 anyway
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jul 15, 2018, 17:05:09
It's traditional to go to nearest number rather than actual capacity (CB400f was 406cc, Z1 903cc, etc)I like the badge idea and wish I'd thought of it. Bike looks purposeful with 550 front end and dual disc's  8)
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jul 15, 2018, 20:35:35
It's traditional to go to nearest number rather than actual capacity (CB400f was 406cc, Z1 903cc, etc)I like the badge idea and wish I'd thought of it. Bike looks purposeful with 550 front end and dual disc's  8)

true true, but the engine casting says 356, actual capacity. I'd stick with 380 otherwise
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 16, 2018, 10:57:22
Parts delivery !.......
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 16, 2018, 17:02:56
The CB390 Lives, again.

Installed the new cam sprocket and bolts ( triple checked amd loctited :-) )

Set cam, valves amd timing and he fired right up.

Couple of cautious test rides and all seems good.

Any advice on Ďrunning iní for the big bore engine?

I ran gently up to 7k, as i dont usually have a tacho on the bike, just a speedo, this sounded quite fast enough!

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sonreir on Jul 16, 2018, 17:25:55
First up, just idle the engine until it's warm.

Then you need to take it out and ride it as soon as possible. Don't rev the engine without load on it.

When riding, rev the bike up to 5,000 RPM in first gear and then let off the throttle and let the engine do the braking. Repeat a few times.

Repeat again at 7,500 RPM.

Now take it out and ride it like you stole it. Avoid staying at the same engine speed all the time; use the whole RPM range.

It should only take 20 miles of riding or so to break an engine in.
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jul 16, 2018, 19:20:55
What he said, but if you have good hills around you use them for engine braking.  Full throttle, off throttle, full throttle, off throttle.  In a way, you're trying to put compression on both sides of the rings to seat them. 
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jul 16, 2018, 21:58:28
I ran my first 378 on a dyno to about 11,500rpm 30~40 mins after building it. It only had a quick ride around yard and a coupler of heat cycles.  :o Having it under load for a few seconds after first start helps rings bed in faster but can cause piston to 'pick up' if your not 'careful'  ;D
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 17, 2018, 12:32:31
Thanks Guys

Iíve done a small run at varied revs up to 7k.

Tonight iíll do a more methodical load/unload run building up the revs.

Then i think iíll recheck valve clearances etc and go for an Italian Tuneup :-)

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 18, 2018, 05:30:27
The CB390 is running well!

Engine seems stronger than before, but i do need to build up my trust in the motor, I built it !, before proper testing.

Will finish running in this week, then retorque the head and reset valve clearances, seems a little tappy to me.

He he is, resting after a test run :-)

Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 19, 2018, 16:58:23
So tonight i thought iíd retorque the head, check things over etc.

Head bolts all just clicked on the torque wrench, so hadnt loosened at all.
I reset the valve clearances, timing and fired him up, oil pissing out of the points cover.
So i put the cam seal back in...... and tried again !

Wow! Running like a sewing machine and pulling much harder than before
Clutch is slipping in third when the engine comes on cam, i had to put the standard springs back in as my Ďhdí ones were shite.....

Two questions for the learned 360 folk?

1, can anyone supply me a set of genuine hd clutch springs, iíve had no luck getting some
2, whats the procedure for dynamic timing the engine, ie at what revs and what advance am i seeking ( i have a timing strobe and know how to use it from my TR6)

Thanks for all the help so far guys, its been a fun upgrade project.

Hereís the CB390 waiting to go out for test ride......

Steve
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jul 19, 2018, 17:39:59
dynamic timing just take the alt cover off - if the bike is on the center stand it won't leak much.

as for springs, all suppliers I know have them are U.S. based
Title: Re: Possibly entering the 378 club!
Post by: advCo on Jul 19, 2018, 17:40:16
Basically with the timing light you want the hash mark to line up smack in the middle of the two advance marks when the motor is running @ full advance which is about 4k rpm.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 19, 2018, 19:07:26
Thanks both

Ive found a local supplier of EBC hd springs, will give those a try.

I have an adjustable timing light, can set desired advance degrees and the flash should line up with tdc mark.

What is the timing supposed to be at max advance, eg 30 degrees before tdc ??

Steve

Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Jul 19, 2018, 21:05:39
manual says advance angle is 0-12.5 with advance starting at ~1800rpm and full advance occurring at ~3400rpm
I guess that means full advance is 12.5*   -
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jul 19, 2018, 21:19:53
Cam runs 1/2 crank speed so 12.5 would be 25 crank angle. Pretty sure I've measured it nearer 35 degrees though so maybe 123.5 is 'F' mark? (It's a long time since I read manual  ;D )
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 23, 2018, 09:24:44
Iím still awaiting delivery of the hd clutch springs and some zener diodes to Ďfinishí the build but the cb390 is running great.

Iíve had a couple of blasts on bigger roads now and feel confident of joining the Ton Up Club real soon !

Thanks for all the help and advice guys, i wouldnít have attenpted this without the DTT forum and your inspiration !
Title: Re: Possibly entering the 378 club!
Post by: Cursh on Jul 23, 2018, 11:02:46
Really beautiful build.


I love the badge hack.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 23, 2018, 11:06:20
Thanks Cursh, i am pleased with how it turned out.

I started searching for Ď390í badges and there are a few Ford ones.
Then it dawned on me, Ďbadge engineering.
Itís almost as rewarding as Ďcardboard aided designí :-)

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 23, 2018, 11:11:56
Cam runs 1/2 crank speed so 12.5 would be 25 crank angle. Pretty sure I've measured it nearer 35 degrees though so maybe 123.5 is 'F' mark? (It's a long time since I read manual  ;D )

Total advance at 4000revs will be static advance plus 2*dynamic/cam advance.

Static could easily be 10 hence 35 total is about right.

Iíll have a test and report back, will be a few days though with work and it being too hot here in London at the moment !

Steve
Title: Re: Possibly entering the 378 club!
Post by: advCo on Jul 23, 2018, 11:13:50
Looking good, glad you got her back together and running
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 23, 2018, 11:17:00
Oh, and hereís the Tacho on a temporary bracket next to the ĎTon Upí speedo.

Speedo is the original with a beautiful new face made by Matt/Sonreir :-)

Steve
Title: Re: Possibly entering the 378 club!
Post by: advCo on Jul 23, 2018, 11:23:31
Awesome. I like the blue backlighting, but does it effect your night vision when night riding?
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 23, 2018, 11:36:43
Awesome. I like the blue backlighting, but does it effect your night vision when night riding?

The speedo doesnt but have yet to try the tacho at night.
Am having trouble getting the tacho to work so ot may not be there long!
Title: Re: Possibly entering the 378 club!
Post by: advCo on Jul 23, 2018, 11:41:28
The speedo doesnt but have yet to try the tacho at night.
Am having trouble getting the tacho to work so ot may not be there long!

I have never had good luck with those electronic tachs that read the pulses on the HT wire. On my XL I plugged the Trailtech tach lead directly into the connector that led from the points to the coil. It was better functioning than I've seen from wrapping around the plug wire lead, but still jumpy and fairly inaccurate.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 27, 2018, 08:34:57
Went for a spin around the country lanes this morning, CB390 running great!

I have a few issues to work on, but 90% there.

Issues are :

Bit of Ďpoppingí from right exhaust on overrun and tickover, iím thinking its an air leak in the exhaust?
Tacho not working, awaiting opto-isolators
Clutch slipping a little, have new springs to fit
Neutral difficult/impossible to get when hot, was like this before
Oil change after rebuild, wondering whether to use fully synthetic or semi?, 10w40.

Steve
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jul 27, 2018, 10:38:01
Whatever oil you use, make sure it meets the requirements of JASO-MA.  Personally I use Rotella T4 15w-40 for all of my wet clutch bikes, but the oil debates are far and wide.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 27, 2018, 11:53:33
Whatever oil you use, make sure it meets the requirements of JASO-MA.  Personally I use Rotella T4 15w-40 for all of my wet clutch bikes, but the oil debates are far and wide.

Thanks, do you use ma1 or ma2 spec oils?
I dont see the rotella much on this side of the pond, usually use Shell Ultra 4t in the Ducatiís which is MA2 spec, but they are dry clutch?

Is fully synthetic appropriate for these old Hondaís ?

Steve
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Jul 27, 2018, 12:02:16
Pretty sure MA2 is an added distinction for bikes with catalytic converters, so either should do.  I use the dino oils, but I think synthetic or conventional is good.  In a climate like Georgia, I don't see much need to pay the extra cash for the synthetics.
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jul 27, 2018, 13:06:13
Thanks, do you use ma1 or ma2 spec oils?
I dont see the rotella much on this side of the pond, usually use Shell Ultra 4t in the Ducatiís which is MA2 spec, but they are dry clutch?

Is fully synthetic appropriate for these old Hondaís ?

Steve
I run full synthetic in mine but it's Rotella again (5W/40 plus 2oz ZDDP per 5 litres) Pretty sure you can get in touch with Shell (they have a forum for bikes) and find out what it's called in Britain/Euriope. Mobile 1 is also OK  for wet clutch (according to Mobile spec shets) Brendon is also using Rotella 5W/40. When I stripped his bike, cam and rockers were in better condition after 2,500 miles than when I originally built it (more 'polished') His cam is also 'gun drilled with drilling's for each bearing and lobe.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 27, 2018, 14:16:37
I run full synthetic in mine but it's Rotella again (5W/40 plus 2oz ZDDP per 5 litres) Pretty sure you can get in touch with Shell (they have a forum for bikes) and find out what it's called in Britain/Euriope. Mobile 1 is also OK  for wet clutch (according to Mobile spec shets) Brendon is also using Rotella 5W/40. When I stripped his bike, cam and rockers were in better condition after 2,500 miles than when I originally built it (more 'polished') His cam is also 'gun drilled with drilling's for each bearing and lobe.

Thanks PJ

I thought zddp was more for flat tappet engines, i have a 1974 TR6 car and we are forever debating which is the best oil for those engines. Mine is tuned to about 180bhp and i favour Valvoline VR1 which is both hin in zddp and comes out near the top in film strength tests.

Wasnt expecting zddp to be an issue on the Honda!

My default choice is Shell Ultra 4T, which is probably overkill but i can then share it with the Ducatis.

Steve
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Jul 27, 2018, 14:39:38
It may not be needed but as I know 250/360 has top end issues I decided tro be safe rather than sorry. The rockers are similar to a flat tappet as they have to slide over cam, but, unlike flat tappets, they don't rotate. (I had an old Rover and a Chevette I was going to 2.3 rally spec,etc but sold it and put motor in Manta GTE  8) Never had Manta over 125MPH but that was 'uphill' late for work one morning
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Jul 27, 2018, 16:36:44
It may not be needed but as I know 250/360 has top end issues I decided tro be safe rather than sorry. The rockers are similar to a flat tappet as they have to slide over cam, but, unlike flat tappets, they don't rotate. (I had an old Rover and a Chevette I was going to 2.3 rally spec,etc but sold it and put motor in Manta GTE  8) Never had Manta over 125MPH but that was 'uphill' late for work one morning

Opel Manta GTE, that takes me back, white i presume 😀
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Aug 01, 2018, 02:39:30
Bike is running great, apart from one carburation issue.

Thereís a hesitation and occasional stall when opening the throttle.

At the weekend i reset the timing and adjusted the idle mixture screws to get a strong idle, bike seemed to be running better than ever.

Out for a test ride and there;s a hesitation on opening the throttle, and occasionally it stalls. This is when i open the trottle to pul away, seems to be worse the faster i open the throttle.

Have i made the mixture too rich do you think?

I am running foam pod filters but havent had this problem before, theyíve been on for a year.

Suggestions please!

Steve
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Aug 01, 2018, 13:22:41
Nope, Black  ;D   The problem with carbs is 'normal'. Around 4,000rpm slide starts lifting and adds too much fuel. If you fit a smaller secondary main jet to 'fix' that problem, you end up very lean around 7,000. If it was possible to fit a needle with longer parallel section it should fix things. It may be easier to find CB160 needles in Britain, I've heard they work but don't have any experience with them
Title: Re: Possibly entering the 378 club!
Post by: MiniatureNinja on Aug 01, 2018, 15:14:01
Nope, Black  ;D   The problem with carbs is 'normal'. Around 4,000rpm slide starts lifting and adds too much fuel. If you fit a smaller secondary main jet to 'fix' that problem, you end up very lean around 7,000. If it was possible to fit a needle with longer parallel section it should fix things. It may be easier to find CB160 needles in Britain, I've heard they work but don't have any experience with them
Ok so is it normal for misfire while cruising at that rpm? Should I cruise at a lower/higher rpm?
Title: Re: Possibly entering the 378 club!
Post by: irk miller on Aug 01, 2018, 15:59:22
Ok so is it normal for misfire while cruising at that rpm? Should I cruise at a lower/higher rpm?
It's not normal.  It needs to be tuned out.  Maybe it's common for 360s, but it sucks and I wouldn't call it normal.
Title: Re: Possibly entering the 378 club!
Post by: advCo on Aug 01, 2018, 16:00:30
Bike is running great, apart from one carburation issue.

Thereís a hesitation and occasional stall when opening the throttle.

At the weekend i reset the timing and adjusted the idle mixture screws to get a strong idle, bike seemed to be running better than ever.

Out for a test ride and there;s a hesitation on opening the throttle, and occasionally it stalls. This is when i open the trottle to pul away, seems to be worse the faster i open the throttle.

Have i made the mixture too rich do you think?

I am running foam pod filters but havent had this problem before, theyíve been on for a year.

Suggestions please!

Steve

Could possibly be a vacuum leak.  Right before I sold my 360 it developed a tiny leak where the intake manifold meets the head. Bike idled great but as soon as you cracked the throttle it wanted to stall out. I was able to get an RPM surge by spraying some ether around the intakes but had to find the EXACT spot, so it was a tiny little vacuum leak. Cut some new gaskets and sealed both sides with Yamabond and off we went.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Aug 01, 2018, 17:00:32
Could possibly be a vacuum leak.  Right before I sold my 360 it developed a tiny leak where the intake manifold meets the head. Bike idled great but as soon as you cracked the throttle it wanted to stall out. I was able to get an RPM surge by spraying some ether around the intakes but had to find the EXACT spot, so it was a tiny little vacuum leak. Cut some new gaskets and sealed both sides with Yamabond and off we went.

Interesting, iíll investigate, thanks.
Title: Re: Possibly entering the 378 club!
Post by: Sonreir on Aug 01, 2018, 18:01:46
You can also try advancing the ignition timing a couple of degrees and see if that helps. Don't exceed the maximum advance, though.
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Aug 01, 2018, 21:42:22
It's not normal.  It needs to be tuned out.  Maybe it's common for 360s, but it sucks and I wouldn't call it normal.
I should have been more specific. It's 'normal' for unmodified carbs. As SD is in England it isn't practical for him to mail them to me for modification but, Dave Silver may have CB160 needles cheap enough to experiment with. A stock 360 needle would be too long if slide is modified to drop it 1mm.(equivalent of going down two notches on adjustable needle)
Title: Re: Possibly entering the 378 club!
Post by: crazypj on Aug 06, 2018, 13:37:49
Sees that Rotella may be Rimula in Britain?
Title: Re: Possibly entering the 378 club!
Post by: erock85 on Aug 16, 2018, 17:37:49
70mm pistons arrived from Japan in less than a week!

Off to the machine shop today 😎
Do you have a source on these pistons? I used the google machine without success.
Title: Re: Possibly entering the 378 club!
Post by: Sderbyshire on Aug 16, 2018, 18:11:36
Yes, i found a seller on ebay and he was very helpful

Email is info@cruzinimage.net contact name Mitsuo

They arrived in a week from Japn to London, no problems with them at all.

Steve
Title: Re: Possibly entering the 378 club!
Post by: Sonreir on Aug 16, 2018, 18:27:20
Do you have a source on these pistons? I used the google machine without success.

This is also an option...
Title: Re: Possibly entering the 378 club!
Post by: erock85 on Aug 17, 2018, 09:10:10
Yes, i found a seller on ebay and he was very helpful

Email is info@cruzinimage.net contact name Mitsuo

They arrived in a week from Japn to London, no problems with them at all.

Steve
Awesome, thank you so much!

This is also an option...

Great! I love options