My clutch issue

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1st Shirt Maxer

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Just wanted to post my clutch issue in the hopes that it might help someone else out. I recently had to replace my diaphram spring so I opted to install a barnette pressure plate. At the same time, I put new steel and friction plates in. (I did align the dots on the plates) After getting it back on the road, I noticed that as I rode longer and longer, the clutch would start sliping. Once the bike fully cooled no slippage so I was baffled. I bleed the system and no change. My only idea was to check the slave cylinder which I had rebuilt several months earlier. What I found was some rust and pitting on the pistons leading edge just below the main seal. I tried to clean it up but once back together the piston would actually bind in the outward/engaged position. I have ordered a new slave cylinder and hopes that fixes the problem, I will report later on the fix but being here in Guam, rust will get into the most unusual places. I've also seen a 2010 Toyota rust from underneath the paint with no chips or scratches, crazy. If anyone has anymore ideas give them to me.
 
Put a violin string or some welding wire into the two little dimples in the bottom of your reservoir. See if one of them releases a fountain of fluid. Get some towels all over your bike first if you like your paint. It could also be that the brass barrel inside the lever is binding out of alignment and not allowing the master cylinder plunger to fully release.
 
I will try the violin wire to see. I have the system completely drained so is there any fix to the out of alignment issue you spoke of? I'm going to tear down the master cylinder and just check everything while I'm waiting on parts.
 
when you pull off the lever, just make sure that barrel moves freely. Neither of the things I mentioned may be your problem, but I know both happened to me. Good luck, and let us know what you figure out.

Posted with my thumbs.
 
Also... I read somewhere if the clutch slips.. rotate the clutch plates 180 degrees from where you have them now... I will try and find the link....
 
They don't slip, what he said is that they work normally but after some riding it starts to slip just like if the fluid gets stuck in the line and doesn't come back allowing the plates to engage.
For what it may be worth when that happens to you and it starts slipping try to undo the slave bleeder a bit and see if it squirts some fluid (do not hold the lever, leave it alone), if that is so your problem is most likely at the master not allowing the fluid to come back.
 
UPDATE :bang head:I tried to reverse bleed my clutch, cover off of master cylinder, bleeder screw opened, syringe full of brake fluid attached and not able to get any brake fluid to push through. Got some guitar string, poked it into the small hole a few times tried again. Still no fluid movement. Opened the bleeder more than a full turn and still nothing. Now frustrated, I pushed so hard on the syringe the tubing popped off and brake fluid squirted everywhere. Lots of cursing, swearing :damn angry:and a slight tantrum later I have pulled the master cylinder to tear it down and clean it. Question, anything specific I should be looking for?:ummm:
 
Are you still running stock hoses. It sounds like a build up in hoses. You are able to push fluid to work clutch but the fluid is not able to flow back into the master cylinder. This would also explain why you couldn't reverse bleed the clutch. Have had this happen to me.
 
You need to check that the master cylinder piston has fully returned after you have applied the clutch.
Remove the lever and see if this will allow the piston to move further out.
If you still can't reverse bleed, then you will need to strip the m/c to see why it isn't returning.
 
Did you try this, Dave? (copied from a previous reply)
Cheers, Miles

Just changed all the fluids last week.
Previously when I did the clutch, I followed Mr. Fire-Medic's suggestion re "reverse bleeding" Worked really well.
This time I thought I'd try a more traditional approach, just to see how it would go.
I mity-vac'ed out all the old fluid, filling the reservoir occasionally, then hooked up a clear tube to the bleeder, the other end in a fluid-filled bottle, then started that old time-honored routine -"3 pumps of the lever, hold, crack open bleed valve, watch the air bubbles in the tubing, close bleeder"
Of course this didn't work. No pressure build up, after multiple bleedings.
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So I added an extra step. After each session of the above, after closing the bleed screw, I worked the lever (pulling&releasing) quite rapidly, with the reservoir cover off. This caused streams of bubbles to rise from the orifice. Once they had stopped, I did another bleeding session. Then another"bubble watch". Then another session. At this point I could feel pressure in the lever. One more bleeding (for good measure), and no bubbles appeared in the tubing.
Probably took about 15 minutes from start to finish, after adding bubble watch thingy.
Still wish the clutch was as easy as the back brake............
Cheers!
 
I do not have stock hoses, replaced it with one from Sean last May. I've already removed the mc so I will check to see if the piston is moving freely and completely tomorrow. It's late here Saturday so I'll tackle this tomorrow. Thanks for the help, I'll update everyone on what I find.
 
Sounds like pressure is increasing in the clutch system as things warm up, but the fluid is not "free" to expand as it needs to. I had the same problem. The clutch was fine when cold, but as she warmed up the clutch would slip. Cracking the bleeder on the slave cylinder would get me home. The problem was in the clutch master cylinder. Some dirt was preventing fluid from expanding back into the master cylinder reservoir; as temp increased the fluid expanded and effectively disengaged the clutch. I used a paper clip (I think) to probe the 2 holes in the reservoir. The bike was hot and when I cleared the dirt brake fluid squirted out and took the dirt with it. It was a bit messy but the clutch has been fine ever since.

Hope this helps and good luck.

Mark
 
Finally had the chance to tear my clutch master cylinder down today, and what I found was awful. I found so much trash behind the piston I'm surprised my clutch ever worked. I was lucky to find a rebuild kit on Guam so I rebuilt it and put it on the bike. After the previous attempts at reverse bleeding, I was surprised at how easy it is when everything is working properly. Got it all together and will be able to take it on a test drive tomorrow. I'm crossing my fingers in hoping I can get my power back.
 

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