1982 CB750F... The resto-not

Jimbonaut

Well-Known Member
DTT SUPPORTER
Well, dodged a bullet. Tipped the engine on its arse and gave it a good shake, pulled the oil pan and saw the little bastard tucked in behind a gear. Bit of wire and fished the thing outta there





Garage gods were smiling after all. And thank fuck for it too. Got the cylinder on (the bottom oil ring on 1 and 4 was a right bugger), took a couple of hours but seating that thing felt bloody fantastic. Def recommend the cable tie routine if you're a pair of hands light. Also cable tied a big wrench to the crankshaft to stop the pistons moving during the job -



Head's on too now no drama (didn't use any copper spray on the gasket so the head gasket went on dry, hope that's ok), installed the cam tensioner and head nuts. All in all, heck of a day. Things are starting to look bike-like again -

 

cb250nproject

If you can make it better do so
He’ll yea..... best feeling ever bro glad it didn’t require a full strip down


Sent from my iPhone using DO THE TON
 

Jimbonaut

Well-Known Member
DTT SUPPORTER
Massive, massive relief =)

Learnt that the cylinder studs on this model ('82 Super Sport) can take more torque than the max 29ft lbs stated in the manual, up to 35ft lbs. Something to do with their construction or what have you. Anyway, torqued them to 34ft lbs (needed to run out and buy another torque wrench - the two I have did not cover this torque spec - from Canadian Tire, on sale, for $60, result 8)) - with a dry head gasket. Cam installation up next.
 

Jimbonaut

Well-Known Member
DTT SUPPORTER
Before I could start the cam install, discovered that the cam holder threads in the head were jammed full of gunk that needed removing, as the cam cover bolts would not thread down at all. So I found a sacrificial bolt of the same spec (in this case M6, 1.0 thread pitch) and cut two long slots down the sides -



Slowly screwed it into the threads until the resistance stopped it, backed it out and all the crap shores up in the slots. Airgun that out and repeat (some threads took 5-10 passes to get everything out) - worked a charm.

Before doing anything, both cam chain tensioners needed to be fully compressed to take off as much tension on the chains as possible to allow for an easy installation. Pulling up on this part of the main tensioner flattens out the plastic "bow" part of the tensioner giving you more room to work -



Same thing with the intake cam chain tensioner - flatten that thing out as much as possible and install the lock bolt on the front of the engine.

Molybdenum grease'd the cam bearings and holders. Installed the exhaust cam, sprocket sitting on cam (not bolted onto shoulder) and exhaust drive chain installed on sprocket making sure the dots on the sprocket align with the head -





- and the engine is at 1 4 TDC -



Lobes of cam on #1 cylinder pointing toward the spark plug, and it this point the notches on the end of the cam should align with the head. They don't though (see below pic) because other cam lobes prevent the cam from seating completely. This gets resolved later though. Making sure the dots on the sprocket are still aligned and the engine is still at TDC, installed A and E cam holders (moly grease on the bolt threads), finger tight at this point -



Install the tach cam holder (after replacing the oil seal inside), making sure the threads on the worm gear align with the threads on the cam, and D cam holder, finger tight again and then bolt all 4 down firmly in a criss-cross pattern -



Going back to the notches on the cam, these now need to be aligned with the head. To do this I used a pair of channel locks, gripped the flange on the cam that the sprocket bolts into and turned the cam enough to align the notches. Note that at this point the sprocket is sitting on the cam, and therefore will not rotate when the cam does (and therefore stays aligned with the head) -





With the cam seated, I could then maneuvere the sprocket up onto the shoulder of the cam, making sure the dots on the sprocket still aligned with the head -



Applied blue loctite to the threads of the sprocket bolts - installed one finger tight (with a rag in the cam chain tunnel - don't need anything else taking a dive down there again), rotate the crank counterclockwise from the left hand side of the engine (holding onto the intake cam chain) 360 and installed the other sprocket bolt and torqued it, then another 360 degrees back to the first sprocket bolt and torqued that one. Torqued the 4 cam holders down to spec in a criss-cross pattern.

Then installed the intake cam, making sure the dots on the sprocket align with the head -



Installed the two outside cam holders, then the two next to them, bolted them down. Cam notches should align with the head -



Installed the cam guides, and then the other cam holders on the exhaust cam - along with the oil pipe - were installed, and the other cam holders on the intake. All torqued to spec.





Job's a good'un.
 

3DogNate

"You Meet the Nicest People on a Honda"
This is gonna be killer when its done if you put this much attention to the rest.
 

Jimbonaut

Well-Known Member
DTT SUPPORTER
Thanks guys, once again I’m definitely standing on the shoulders of giants. I had a lot of help with the more technical aspects of the rebuild from the guys over at the cb1100f.net forum - so a big shout out to them. That forum is an absolute goldmine for the 1980’s Super Sport CB series and well worth a look. Lots of technical info, mods and advice on what can be done with these bikes.


Sent from my iPhone using DO THE TON
 

Jimbonaut

Well-Known Member
DTT SUPPORTER
I need to buy an impact wrench. Very need.

Found myself sitting on my engine - which in turn is sitting on my workbench - holding a 2' breaker bar with a strip of steel wedged into the ribs of my clutch in what quickly became a farcical attempt to remove the clutch bolt. It's not happening. I need torque. I need tools. I need an impact wrench.

It doesn't need to be cordless (would be nice though) as from what I can tell the corded ones are cheaper and I don't need to march the thing all over the joint anyway. Anyone got any recommendations? What kind of max torque do I really need anyway, considering this'll mainly be used for moto applications (any the occasional lug nut)? I've seen some for around $200 CAD, not brushless but battery operated with max torque of around 150ft lbs.



Not. Happening.
 

doc_rot

Oh the usual... I bowl, I drive around...
DTT SUPPORTER
DTT BOTM WINNER
if ebc makes a clutch holder tool no impact is needed.
 

Jimbonaut

Well-Known Member
DTT SUPPORTER
After some recommendations and online sleuthing, picked up this menace to society for a great price. There have been a few occasions where a bolt has been my undoing, however -



- no longer. This thing is the absolute dogs bollocks, got the clutch nut off without blinking. Winter tire changes are going to be a walk in the park with this thing, and with 450ft lbs of torque I can't imagine many situations where I'd need more. Unless that build-an-Eiffel-tower itch needs scratching.
 

Jimbonaut

Well-Known Member
DTT SUPPORTER
Pulled the clutch apart -



and glass bead cleaned the steel plates -



Ended up doing it myself, so that's that off the bucket list. Always thought it must be a very satisfying job, using one of the bead blasting cabinets to clean shit up - was not disappointed.

How do you guys clean friction plates? Kerosene?
 

Jimbonaut

Well-Known Member
DTT SUPPORTER
Powdercoated frame's been sitting in the garage for months. Felt good to get the engine in the thing -

 

3DogNate

"You Meet the Nicest People on a Honda"
Jimbonaut said:
How do you guys clean friction plates? Kerosene?
Throwing money at Bike Bandit gets the job done too... those friction plates are 37 years old man, they might get the job done but that's really old for a consumable.

https://www.bikebandit.com/1982-honda-750-super-sport-cb750f-clutch-parts/pl1/m151786?f=2
 

Jimbonaut

Well-Known Member
DTT SUPPORTER
Fair play yeah, when you put it like that it makes sense to replace these with new. EBC?


Sent from my iPhone using DO THE TON
 

3DogNate

"You Meet the Nicest People on a Honda"
Jimbonaut said:
Fair play yeah, when you put it like that it makes sense to replace these with new. EBC?


Sent from my iPhone using DO THE TON
EBC is where the perfomance:cost ratio lies with me... I Think i used Barnett on my T120R and EBC on everything else I've ever done.
 

Jimbonaut

Well-Known Member
DTT SUPPORTER
Really do learn from experience. Last time I tried removing wheel bearings it literally took me days and many, many trips to Canadian Tire to buy different sized concrete anchors. Now that I know the anatomy of their inner workings, this time it took about 20 mins -



Any suggestions on how I can clean up the brake rotors?

 

DTT Bike Of The Month Gallery

DTT Light or Dark

www.cognitomoto.com
https://www.townmoto.com
www.speedmotoco.com
www.jadusmotorcycleparts.com
www.lostapostle.ca/
www.sparckmoto.com
Top Bottom