1982 CB750F... The resto-not

Maritime

Active Member
irk miller said:
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
 

The Jimbonaut

Active Member
Maritime said:
+ 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.
 

The Jimbonaut

Active Member
irk miller said:
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.
 

jpmobius

where does this go?
DTT BOTM WINNER
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.
 

doc_rot

Oh the usual... I bowl, I drive around...
DTT BOTM WINNER
+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.
 

The Jimbonaut

Active Member
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 -



- 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.



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 -



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 -



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.
 

farmer92

Member
The Jimbonaut said:
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.
 

doc_rot

Oh the usual... I bowl, I drive around...
DTT BOTM WINNER
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/
 

irk miller

You've been mostly-dead all day.
DTT BOTM WINNER
+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.
 

pidjones

Active Member
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).
 

ex119x

Member
.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.
 

The Jimbonaut

Active Member
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 -





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 -



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.
 

The Jimbonaut

Active Member
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.
 

wozza

Member
The Jimbonaut said:
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
 

teazer

Active Member
DTT BOTM WINNER
Or get some longer bolts for the shock lower mount and fit spools on those. Easy peasie
 

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