Topic: Reassembling a CB750 K4 Primary Drive with a K6 Clutch Basket

[Stoli]

I am putting the cases of a CB750 K4 back together. At some point the entire clutch basket was cannibalized so I am using parts from a K6 to make it whole.

Notes:

- Both engines were seized when I got them so I don't know any history.
- The K4 (top and bottom) is in better shape so I want to use as much of that as possible.

There was a change on the K6 where they introduced a circlip that held the clutch outer drum on to the transmission mainshaft. If I haven't mixed up my parts, this change also included a splined washer (some sort of spacer I believe).

So – my question is, can I just use the basket (outer drum and everything in it) from the K6 while retaining the primary drive from the K4? It seems to fit OK and the only difference that I can see is that the outer drum is not affixed to the mainshaft with a circlip (and there is no need for the splined washer).

The other option would be to use the sprocket assembly from the K6 as well (that will allow the use of the circlip retainer, but there seems to be a little play in the sprockets on the K6 and the K4 sprockets are solid.

[Stoli]

Well, didn't get any replies so I am forging ahead with the K6 drum on the K4 mainshaft. Just sealed up the cases. Can't find any reason why it won't work. Found a post that sort of addressed the issue and the big difference is that I will use a splined washer spacer instead of the circlip retainer that the K6 used.

After reading 2 hours worth of clutch threads, my head is swimming. Most of the threads address the 2 different kind of friction discs (blocked and angled oil channels) as well as the different combinations of friction and steel discs. This clutch had 6 steel and 8 friction and the friction were all the same kind (sort of a hybrid blocked and angled). The friction discs look worn (and one was cracked) so I need a new set of those but 5 of the 6 steel look good so not sure what to do there. One was slightly warped but not too bad. They are the kind with the dimples which I guess are good. After all that reading I have no idea what discs to buy, how many to buy and if I can replace one steel or if I need a whole set. Cycle X has an entire set for $110 and they haven't failed me yet so I am leaning toward them.

I will drill some extra holes in the inner drum. That seems like a no brainer.