Topic: Weird clutch issue

[Big Bob]

I recently rebuilt the clutch on my 1970 CB 750.

Here's where it gets weird:

I have to turn the adjuster screw all the way in to get the clutch to work.  There is literally no more adjustment range left - the screw is all the way down.

That said, the clutch owrks great.  New plates, new discs, heavy duty springs.  But when it comes time to adjust the thing I'm screwed.

Do I need to add plates or discs?  I do not recall off the top of my head how many were in there initially.  Will adding discs or plates bring the screw out to the point where it does something useful?

TIA for any help.

[Jonesy]

When you say adjustment screw, you mean the screw in the clutch center? I thought I remember reading somewhere that this is to be somewhat expected when rebuilding a CB750 clutch. Did you soak the plates in oil for a few days before you rebuilt it? The plates absorb oil and swell a bit over time, and this will help take up the slack in the adjustment. I could be wrong, though...

[Big Bob]

When you say adjustment screw, you mean the screw in the clutch center? I thought I remember reading somewhere that this is to be somewhat expected when rebuilding a CB750 clutch. Did you soak the plates in oil for a few days before you rebuilt it? The plates absorb oil and swell a bit over time, and this will help take up the slack in the adjustment. I could be wrong, though...

I soaked the discs, by this I mean the ones with the raised bumps that are made out of cork or asbestos or cheese or whatever they make the tings out of these days.  Not for a few days, maybe an hour, tops.

The screw I refer to is the one in the center.

[low-side]

Soaking them for an hour probably just got them wet.  It may take a while, but I bet you'll need to back that screw out soon.

[RabbleRouser]

Big Bob

I read you post of 9/26/05 and I had exactly the same problems you had with the adjustment of the clutch after I replaced the steels and clutch friction plates (Clutch cover adjustment screw turned all the way in and both cable adjusters screwed nearly all the way out).

Did soaking the clutch frictions correct the problem or was it another issue?

I have tinkered with my clutch several times adding and subtracting clutch steels but each time the conclusion was as though the new Honda clutch cable is too long or the adjusting bolt in the clutch cover is too short.

Please let me know if you had any success with this issue.

Thanks!!

My Bike: 1972 Honda CB750-4

[bwaller]

I bought some discs from Mark @ M3 years ago and they were thinner than the original. I eventually lengthened the adjusting screw slightly in order to adjust.

[RabbleRouser]

Thanks for the reply:

I often wondered if the length of the clutch cover adjustment screw was the culprit.

With the adjustment screw turned nearly all the way in, the "pin side" of the adjustment screw doesn't quiet reach the clutch lfter center.  This leads to adjusting the rest of the slack with the cable adjusters which when finished, are nearly ran completely out (hanging on by a thread or two).

If you could, can you tell me how you modified the adjustment screw to make it longer.

Thanks

 

[RabbleRouser]

Has anyone else had this problem? 

I'm not sure what the solution could be other than blindly begin changing parts.

[Big Bob]

I tried all sorts of fixes.  Swapped plates, took apart another clutch on a different bike to compare, soaked discs in oil.  No joy.  I re-assembled the thing, turned the screw all the way in, and ran the bike through a track day and two race days at Barber.  The bike performed flawlessly.  I wish I could say the same for the rider.

My launches were top-notch, best in my class.  I beat out several guys who are much faster than me.  Too bad the races aren't settled in the first 200 feet or so.  No I don't want to try drag racing.

My point - aside from the adjsutment issue the clutch was fine.

The engine is out of the bike now.  I'm doing a bunch of stuff to it in preparation for the upcoming racing season.  New gaskets and seals all around, new cam, general clean-up.  While I'm at it I'm going to examine this clutch thing and sort it out.  I will post my results when I know something.

[Magpie]

You may want to read this article on clutchs in the tech library at http://sohc4.us/?q=node/44
I've just had my clutch out and will do it all over again to be sure I've reassembled it the article suggests to. It seems like a good thing to do. Don't know if it will solve the problem tho'.
Cheers,
Cliff.

[Sam Green Racing]

OK guys, I think you will find the answer in FAQ, if not try to follow this as I have had the problem twice.

When you are assembling the clutch, the part with the four pillars that stick out towards you that the springs go over must be located properly, then you need to try to keep it pulled towards you as you assemble the plates.

When you remove your cover, you will probably find your clutch all loose.

If you dont get it in spot on, it catches on a lip at the back of the drum, then when you have finished as soon as you try to set the adjustment it all comes loose.

Hope you can understand all that.

Good luck. Sam.

[RabbleRouser]

Thanks to all who responded to this issue.  I will be continuing my bike rebuild soon and if I get this clutch issue worked out, I'll post my fix.

[Sam Green Racing]

 

[cd811]

I like your reaction sam

[dusterdude]

cmon bob,take a whack at drag racing.i am

[Sam Green Racing]

Tell us more Dusty.

Sam.

[Magpie]

i MAY have found a solution to the weird clutch issue. Please go to the "Broken Pressure Plate" thread to review it. Sorry, it's too long to duplicate here. Cliff.