Clutch still slipping

[martin]

Well I guess I jumped the gun in hopes that replacing the clutch spring and adding the JW's would solve the slipping problem.
Now that I've taken the bike for a long ride where the oil got good and hot the clutch began to slip again. I guess I should have replaced the friction plates while I had it apart.
So I'll be ordering the friction plates but was not sure about the steel clutch plates. The Kawi parts breakdown shows 3 different thickness plates but I'm not sure which I need if any.
Appreciate any help and suggestions.

[gillisfire]

I had the exact same problem you are having. I changed the clutch springs, changed the clutch fluid a couple times, cleaned the master cylinder real good, and changed out the clutch line. Doing all that I would still have a issue with the clutch after riding for a while. I was on the verge of tearing into the clutch plates. But then I had an idea! What if the problem was in the clutch master cylinder?

If after sitting for a while, you can ride with no issues. And after a while, when your bike heats up, you would have a issue that seemed like your clutch was slipping. I am sure you changed the brake fluid and cleaned the small fluid return hole in the master cylinder. What was happening on my bike, in the master cylinder there is a rubber sleeve that goes over the lever spring. Mine had formed a small tear that would cause it to not form a suction to pull the fluid back into the master cylinder. So each time I actuated the clutch, it would put fluid into the supply hose and build up pressure in the slave cylinder. This would make it seem like it would only act up after my bike got hot. Letting it set and "cool off", the fluid will slowly be pushed back into the master cylinder and release the pressure on the slave cylinder.

I ordered a rebuild kit for the master cylinder off of Ebay. Changed out all the parts for the master cylinder and cleaned it up real good. Installed fresh fluid, and have ridden a couple hundred miles and haven't had a issue yet. So maybe you are having the same type of issue. Try getting a rebuild kit, this is the one I ordered:

http://www.ebay.com/itm/Clutch-Maste...92c84c&vxp=mtr

[cactusjack]

Just out of curiosity, what kind of oil are you using?

[martin]

Thanks for that "Gillisfire", very interesting and I did read your earlier post regarding similar issue so was curious how you made out. Did you ever change all the friction plates?
I will wait for some more responses but your fix makes sense so will keep that in mind. I have not flushed out my clutch fluid yet so this may be the time.
I am using Valvoline 20W50 Motorcycle oil.

[gillisfire]

No, I did the rebuild on the master cylinder and everything seems to be working good. My clutch is ALOT more responsive and makes my bike alot more fun to ride. So I left the friction plates alone.

The way I figured out it was a cylinder issue, I would ride for a little bit and after a while it would seem like I was loosing power. Roll the throttle and hear the engine rev up but not take off. I would keep a 12mm wrench in my vest pocket, so when I would start experiencing this problem I could quickly bump "open and close" the banjo bolt on the master cylinder. This would release the pressure on the slave cylinder and make my bike operate correctly for a while until I worked the clutch again to build up pressure.

So you can try doing this to see if your master cylinder is your problem. Go for a ride and when you start having an issue with your clutch, bump the banjo bolt. It's the bolt holding the clutch hose to the master cylinder. When you bump it, make sure your not touching the lever, you want to do the bump with the lever out and you can do it while riding. Keep a rag with you because when you bump the bolt, it is letting a small amount of fluid out. The fluid is brake fluid and will eat away the paint so you want to wipe it off. If your bike acts correctly after bumping the bolt, then you have an issue with the master cylinder, order the rebuild kit.

Oh, and I am using Mobile 1 20\50 synthetic motorcycle oil.

[martin]

Well that sounds like it might be my problem because when it was slipping pretty bad I took the bike onto the interstate and road gently back home for about 20 minutes. Once I came off the interstate and stopped, the clutch worked better for the first couple of shifts. I guess until pressure built up again. I will give your test suggestion a try.....thanks.

[gillisfire]

Give it try and post back on what you find.

[martin]

I've received the rebuild kit (same one you ordered Gillisfire) and plan to install today. Just wondering if you had any directions for the orientation of some of the parts i.e. the main plunger and rubber seals/washers.

[gillisfire]

I pretty much just payed close attention on how things came apart. But I did also use the parts diagram on this page when I wasn't sure: http://www.cheapcycleparts.com/oempa...aster-cylinder

The hardest part of the hole thing is dealing with the snap ring. If you can get that out and back installed, then you shouldn't have any problems.

[martin]

I know what you mean about the snap ring, I couldn't even see it. Anyhow, before pulling the master cylinder appart I changed the fluid, which was quite dirty, to the Valvoline Synthetic and flushed it out good. Took the bike for a good 30 mile run in town, so plenty of shifting and heat. Clutch was working fine with no detectable slip. Going on a long run today and will keep you posted.
I kept the rebuild kit just in case.

[dshelly]

I know you guys said you are using 20W-50 oil in your bikes but don't you think that's too heavy? Others on here have tried it and have switched back to the recommended 10w-40 like the manufacturer suggests. 20w-50 seems to be fine in an air cooled bikes but with these being liquid cooled I think the 10w-40 works better. If your bike runs hot then try some water wetter or blue ice coolant instead.

martin, you said you switched you clutch fluid to Valvoline synthetic? So dot 4 right?

[gillisfire]

I can not answer for Martin, but I use the 20/50 synthetic due to the heat we deal with. I am about a 30 minute ride to the Gulf of Mexico. So our spring, summer, and most of fall seasons the temps are in the mid 80's and up. In the summer it is normal to be close to 100 degrees out. So you can imagine the temperature coming off the black top. So I found my bikes handle the 20/50 oil alot better. I have also added some Blue Ice to my radiator fluid. It helps to keep my bikes running a little cooler. I ride with some friends that have 1500's and 900's and find my fan doesn't come on quite as often. And it is fun when I ride with my friends that have Harleys, you don't want to leave them running and sitting for very long. But as an example of what type of heat we have here, it is Feb. 2nd and it is 78 degrees.

And Martin, Hopefully you have your problem fixed. If it does act up, go ahead and try rebuilding the clutch master cylinder. Then you can rule that item out for sure. And you are using DOT 4 brake fluid rite?

[Silent Sam]

..I changed over to a Barnett Clutch Spring at a little over 45,000 miles, on my 02 Nomad..
When I took the clutch apart, I Micrometered..all the clutch disc's and plate's EVERYONE of them "mic'ed out" at NEW..(measurements were according to the shop manual)

Dont waste $$$ on new dic's or plate's til you have the old parts mic'ed !..odds are if you have a slipping issue..its the clutch spring....or perhaps, a hydraulic system problem !

[martin]

OK, time for me to fill you all in. As I had mentioned above, I went on a longer ride yesterday and low and behold the clutch started slipping again. After running about 100 miles I turned around and just before home it started slipping quite bad so I tried your trick Gillisfire, to bump the banjo fitting at the master cylinder and sure enough released the pressure build up and bingo no slippage the rest of the way home.
I suspected there was still some crap from the old brake fluid so I flushed out the system once more real good and cleaned out the master cylinder so now the clutch fluid is crystal clear and I took of on a 75 mile run with absolutely no more clutch slipping.
To answer some other questions, yes I am using 20W50 for the same reason as Gillisfire, I'm riding in Florida and the temp is hot. I will try the Blue Ice to help cool the engine. And yes I am using DOT 4 brake fluid.
All is well now so thanks to everyone again for all input.....what great help.
Martin

[gillisfire]

Hopefully you are correct about having some crude left in your fluid and your problem is fixed. But what happened with mine is after changing the fluid, everything would be good for a little while and then start acting up again. I had to keep bumping the banjo bolt until I finally rebuilt the master cylinder. The rubber seals in the cylinder are not pulling a suction to pull the fluid back off the slave cylinder. That's why when you bump the banjo bolt, it releases the built up pressure. And the hardest part of rebuilding the master cylinder was dealing with the snap ring. So far I haven't had anymore issues and I am saving money from having to buy brake fluid to refill what I would loose after bumping the banjo a couple of times. So just keep this in mind.

And thanks for keeping us updated. Hopefully if someone else has a similar issue, this may help them.