Topic: Clutch Woes

[AtlTech]

Finishing off a top and bottom end rebuild of a 1978 750F. Engine has been buttoned up and is back in the bike with minimal issues except that I cannot figure the clutch out. The issues are

• The center adjustment bolt for the clutch (the one with the locknut) must be backed almost all the way out if I'm trying to adjust it as the manual specifies (i.e. unscrew, then tighten until resistance is felt and back out 1/4 turn). Doing this leaves the bolt maybe 1/2 turn from its farthest 'out' position.
• When adjusted to the manual's specifications, the bike absolutely will not roll when in gear with the clutch pulled in.
• The bike can be made to roll with a great degree of difficulty if the center bolt is tightened further, but its 1 or 2 turns past when resistance is first felt
• When the bike is made to roll in this way, the circular clutch cover does not sit flush in place. The center adjustment bolt presses against it and can actually be heard hitting the cover when the clutch lever is released.

Some other things to note:

• The clutch pack is 1000% installed with the teeth meshed together (I actually didn't do this the first time and cracked the lifter plate).
• The lift plate is off of a 1974 750K.
• The shaft that holds the clutch basket is off of a donor engine of the same year and trim, but unknown origins before that.
• The splined washer is in place behind the clutch plates and the convex washer is in with the raised side pointing outwards
• The lift plate has been tightened down as far as it will go
• The irregularly-shaped clutch cover may also not be completely tightened down, but it doesn't leak oil
• The bike has been run for ~5 minute test rides. It pulls a little bit when put in first gear, but nothing crazy. After being run around the block, shifting well and generally behaving, it is much easier to push the bike with the clutch in. But this goes away as the bike cools

That's all the info I can think of off the top of my head. Any suggestions as to what I might be missing or other things to measure?

[The Lone Builder]

I had similar problems.

Screwing the ajuster in (clockwise) will disengage the clutch I believe. From what you say it sonds like you have it just not quite disengaging. When warm, the oil is a little thinner and the drag reduced so all is well. As oil cools, drag returns.

I would screw the adjuster in a bit more and see if this works.

This is based on very limited experience, so if someone else suggests something else, or rubbishes what I said, maybe listen .

Sean

[AtlTech]

Sean,

You're for sure correct about the adjuster. Clockwise and in disengages the clutch a little more.

I've actually tried tightening a bit more, but the bike will begin to roll forward while in gear (clutch out). This is with great effort, mind you. And then pulling the clutch in, it doesn't seem to roll any easier. It almost seems like actuating the clutch lever isn't pushing the lift plate far enough, now that I type this out.

[AtlTech]

Ok, so after a bit more searching, it seems I have a new best guess for my issue.

According to http://forums.sohc4.net/index.php?topic=105983.0 from Hondaman, the clutch lift plate does vary a bit from year to year, at least in thickness. May explain why my adjustment screw is all the way backed out if the K4 lifter plate I'm using is thicker than the 78 F lift plate. I think I'll order a new lift plate to swap in and see how that does.

Anyone know if the K8's will fit the 1978 750F?