Motorcycle Repair/what is the torque spec on clutch bolts?
I have a 1982 honda cm450E that i am re building a clutch on. It went out on me yesterday… When going back together what is the torque spec for the four bolts that hold down the springs? i want to do this right and wasnt sure if there was a specific torque specification that needed to be followed for proper clutch performance. also what is the tolerance on re-using the intermediate plates/discs. (sorry heavy duty truck mechanic here and not sure what to call them. they are NOT the friction plates, but the other, internally splined discs) i ran my finger along all of them and none are grooved or worn. can i still get use out of them? thanks for your help!
Evan, I appreciate your attention to detail, but the torque values on bolts are the same no matter where they are. 6mm bolts get about 4.5-5 ft. lbs. in aluminum. See:
for torque guidelines.
The bolt torque has nothing to do with the clutch spring pressure tension, unless they get left loose. You are tightening them down until the flat washers bottom out on the inner clutch hub bolt stands. Changing spring pressure would be the only way to increase tension on the clutch assembly.
The steel clutch plates need to be FLAT for best results. Just a few thousands of an inch is about max spec. Lay them on a flat piece of glass or a surface plate and see if they are laying down flat or lifting at one of the edges. If the clutch has been slipping very much, that often warps the plates, but sometimes they come away unscathed. Scuff them up on some emery cloth, then wash them thoroughly before installation.
for part numbers and nomenclature.
Check the inner and outer hubs for any notches in the splined areas where the clutch pack moves back and forth. You can smooth out small defects with a flat file.
The clutch lever should have about 1/8" of free play, so you ensure that the clutch pack is fully engaging through spring pressure. I am assuming that you are replacing the friction disks that were worn down below specs. These are pretty sturdy bikes, so clutch failures are somewhat uncommon, I think, given good maintenance and quality m/c oils.