confusion is reighning supreme here. how do i know wchich exact parts i got with no numbers on them? is there a way to tell by measuring? I thought the clutch centers were different as well as lifter plates...i know baskets are different. I have a confirmed 74 motor....with a factory 72 clutch. i have a 72 motor that i had to piece together a 73 clutch for. all this boils down to installing the clutch plate b out of a gl1000 to fix the rattle. Is ther a difference as well in the clutch covers...should i use one over another if i do this? Please help sort this out....nid is going nuts looking at parts fiches and part numbers that appear to be the same from year to year.
Unfortunately...almost every parts fiche I've seen since they went to microfilm in the 1980s is wrong on the CB750. The K0-K1 clutch had 6/6 fiber/steel plates, the later ones had 7/6 fiber/steel. The first plate in on the later ones is fiber, same for most of the K0 clutches. The parts fiche all show first plate in to be steel.
There are some sandcast differences where the steel did go in first, but I won't go into that since you're not there...
The later hubs (and matching pressure plates) are "one plate longer" as the result: in production it appears that sometimes the longer pressure plate got mixed with the shorter hub, causing the famous "loose plate scenario" that can be fixed with a single thicker plate. That's the "cheap fix", BTW: the "right fix" is in swapping the expensive pressure plate instead. Or the hub, to match the pressure plate's finger length. Honda came out with that famous "GL plate swap" fix-up to save them some $$.
If you're struggling with the K2 clutch parts, look into K1 parts instead. Many K2 engines had K1 clutches. One way to check: see if there is a steel band around the boss of the splines on the back of the clutch basket. That's the K0/K1 basket. The hub and pressure plate set from either the K2 or K4 will fit, so long as the right hub and pressure plate are mated and have the right combination of 6/6 or 7/6 plates. Be sure the right springs come along for the ride: if you've mixed them together, use the shorter springs for the K1 hub (6/6) version.
The plates themselves don't matter, so long as the cork blocks are "square" cut: the cork ones must be between 0.141" and 0.121" thick to be considered 'good'. Lay them on a plate glass, try to slide feeler gages under their edges to see if they are warped. Honda says 0.012" is too warped: I find they drag pretty badly starting at 0.006" warp.
