Clutch slipping running out of ideas.....

My clutch in the '82 XJ650LJ slips terrible when the turbo comes on. I changed out the fiber discs and springs with Yamaha parts but still have the problem. The steel plates looked like new with no signs of warping or over heating. Works great until the boost kicks in and the HP goes up...

I'm thinking of adding washers as spacers between the bolt heads and the springs to increase spring tension???

Any suggestions or previous experiences would be greatly appreciated.

 

What kind of oil are you using? Synthetic oils are sometimes at fault for slipping clutches. I understand the desire to use the best oil you can to protect the turbo but motorcycle rated conventional oils really are the best way to go. An oil change stands a better chance of fixing your issues than pre-loading the clutch springs. That stands a chance of breakage in the clutch basket. It may take more than a single oil change to fix the slippage .

 

It's on it's second change of Rotella 15w40 non-synthetic. I use this in my other older bikes without problems and figured it would be fine in this bike too. The Rotella is listed as JASO MA/MA2.

 

I have Barnett clutch springs in mine with the original plates.
No slipping, even ran 16 psi boost for a while.
Your friction plates might be glazed up and probably require replacement with the springs.

 

Couple of hours with a flat surface and an abrasive would be my starting point. Flat surface to check the steel discs are flat, then as @Simmy says, if the are glazed, deglaze them. Refit with original springs, new bolts. Updated springs might be an idea. Be careful with the bolts, they don’t take to over tightening very well..

 

Okay, you beat me to it. That is the oil I use most of the time as well. I guess next is @Simmy's suggestion of glazed friction plates and Barnett springs. Or @Minimutly's suggestion of deglazing the friction plates. I think that if you have already had the clutch apart, you said you have new Yamaha friction plates, that new bolts would be an excellent idea. It is a real mess when 1 snaps off. They don't seem to be forever parts. Good luck.

 

The point about not being flat is, if they aren’t, the “bite” point is vague, meaning adjustment is difficult - too tight it slips, too loose it drags...
Whilst you are checking this, clean the fibre plates with a suitable solvent?

 

On my bike (XS11) it doesn't take much to get my clutch to slip if the adjustment isn't set right. It could be I need newer friction plates, steel discs, springs or even a new cable BUT by fiddling with my adjustment it goes away so I've never bothered trying to replace parts that probably don't need replacement.

 

I would bead blast the steel plates, I do it in every clutch I rebuild as the steels become polished over time

 

Wow, thanks for all the input guys! I'll check out the steel plates and look into getting some springs and bolts. I'll also adjust the clutch so that it just barely disengages and see if that offers any improvement.

What would be a good solvent for cleaning the fibre plates?