Author Topic: Clutch question  (Read 5252 times)

Offline Cold Streak

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Re: Clutch question
« Reply #40 on: November 06, 2019, 02:18:38 PM »
I'm a little late on posting to this thread but I had the dreaded floppy clutch lever.  For me it was when I was cruising down the highway, not using the clutch at all, but sometimes after stop and go.  I'd reach for it after a bit and there would be nothing there.  After bleeding it a number of times the traditional way with the same problem recurring, I went to the Kawi dealer to ask them.  The tech there said he'd seen the problem a number of times and the only way he fixed it was to replace the clutch line.  Since my bike had 70k miles he said that was probably my cure.  I installed a new clutch line and rebuilt the master cylinder.  Bled the clutch both traditionally and with a vacuum device.  I rode for a couple of months with no issues.  Ahhh, victory!  Nope.  4th of july weekend I got stuck in stop and go traffic on a 90F+ day and suddenly I only had half a clutch lever.  I managed to coast down the road with the clutch pulled in, only cycling it occasionally.  After a few miles the clutch came back, almost like the air or whatever found it's way up to the reservoir.  It's been fine ever since, about 5-6k miles. 

In the meantime, I've bought a sst line for both the brakes and clutch.  I've replaced the brake lines but not the clutch yet. I'm waiting until I don't have any rides scheduled for quite awhile.  I will also rebuild the slave cylinder at that time. 

I have to add that I think the Kawi clutch line is one of the stupidest designs I've ever seen.  It transitions from rubber to steel a number of times for no real apparent reason.  I think all those transitions are places for air to get trapped.  I'm not sure where the air comes from, at  least in my case, since the bike had been working fine and I do periodic fluid changes on both the brakes and clutch system.

This has been the only real problem I've had with the bike for 78k miles so I am very happy but also perplexed about this phenomenon. 

Offline maxtog

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Re: Clutch question
« Reply #41 on: November 06, 2019, 03:59:45 PM »
Yeah, I am guessing one will never have problems, as long as air was never introduced to the system at any time.  But once air gets in there, it seems very, very difficult to get it all out.  And it can hang around for a long time, collecting and moving, causing problems and then no problems, and then problems again.  This seems to fit with people who have had zero problems flushing the lines that never allowed air in (I had no problem, for example, but I also never let air in).
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Offline strum

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Re: Clutch question
« Reply #42 on: November 06, 2019, 08:07:51 PM »
 Cold Streak Im going out on a limb and saying this is not air . Before you do anything else take your slave cylinder apart. You said you rebuilt the master but if the slave is sticking(not returning) there is your floppy clutch lever. Rebuild it. Then use a pneumatic bleeder such as Mityvac mv6830  or (what i use now)  Harbor Freight pneumatic brake bleeder.   If you pull that slave apart please let us know what you find . HTH

Offline Boomer

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Re: Clutch question
« Reply #43 on: November 07, 2019, 03:40:22 AM »
The problem here is air in the clutch line.
When the bike warms up, the air expands and partially disengages the clutch, hence the floppy lever.
Once ya get moving the fluid cools down, the air contracts and the clutch behaves normally again.

The ONLY solution I found on my 08 was to PUSH the brake fluid up from the Slave cylinder to the Master cylinder with a big syringe.
Doing it and keeping air out of the system is not easy, but do-able. Ya need to be slow and methodical.
Since I did that I no longer get floppy clutch when riding in dense traffic on hot days.
George "Boomer" Garratt
Wickford, UK


Offline VirginiaJim

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Re: Clutch question
« Reply #44 on: November 07, 2019, 04:12:48 AM »
This happened to me a couple of times but bleeding and refreshing the fluid helped.  These bikes are getting some age on them now and this is all probably related to seals and lines.
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Offline strum

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Re: Clutch question
« Reply #45 on: November 07, 2019, 05:45:46 AM »
 Not trying to be argumentative but he said it was fine for a couple of months. and then in stop and go traffic it happened again. I have a hard time buying that for a couple of months the clutch was good and somehow air  caused this issue. I know these are hard to deal with . believe me ive had my moments with C14 clutch bleeding. I still say its the slave.   Stop and go traffic it was being used a lot and the piston seized then un-seized.  Take it apart. I bet 20 bucks its full of crud. 78k miles he said.

« Last Edit: November 07, 2019, 01:47:41 PM by strum »

Offline Cold Streak

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Re: Clutch question
« Reply #46 on: November 07, 2019, 07:27:34 AM »
I'm hoping Strum is correct and when I replace the clutch line I'll be rebuilding the slave cylinder also.  The way it comes and goes it doesn't seem like it could be air in the lines, because that would be a more constant problem.  The rep from Galfer told me he had similar problems on his Ducati until he rebuilt the slave cylinder.  I'm not going to do it until mid next summer though so I hope I can remember to post back here.

The Kawi tech may have been partly correct when he said i needed to replace the clutch line.  If the line is starting to shed particles due to age it could cause problems in the slave cylinder.  Putting in a new line and flushing out the debris would solve it.

Offline dvitous

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Re: Clutch question
« Reply #47 on: November 07, 2019, 08:26:32 AM »
I just had the same thing happen on my C10.  Went to grab the clutch, and suddenly it seemed that there wasn't much there.  Only a few stuck shifts that took a pull or 2 to make, but it definitely gets your attention!


I also went and replaced fluid and bled the system (installed speed bleeders years ago works great!).  A lot better, but still not sure it's where it should be.


Original lines on my '99... so at 20 yrs old, perhaps it's time for an overhaul?
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Offline lather

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Re: Clutch question
« Reply #48 on: November 08, 2019, 06:40:48 AM »
In September I had a funny clutch lever  on my 08 with 80K. The lever was not returning all the way but the clucth was still working. I flushed the fluid and all ahs been well since.
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Offline PH14

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Re: Clutch question
« Reply #49 on: November 09, 2019, 12:17:49 PM »
I had the lever go to the bars with no pressure condition when cold early this season. I was taking it in for Pennsylvania inspection, and told the mechanic. He changed the fluid while I was there using their vacuum bleeder and I have not had the problem since. The best part was he didn't charge me for the fluid or labor. It does pay to develop a good relationship with a dealer and mechanic. I do most of my own work, but I've known Ken for 20 years or so. I buy my parts and tires from that dealer. I was going to bleed the brakes when I got home, with a MityVac, but I'm glad I didn't have to .

Offline Boomer

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Re: Clutch question
« Reply #50 on: November 11, 2019, 03:08:46 AM »
Not trying to be argumentative but he said it was fine for a couple of months. and then in stop and go traffic it happened again. I have a hard time buying that for a couple of months the clutch was good and somehow air  caused this issue. I know these are hard to deal with . believe me ive had my moments with C14 clutch bleeding. I still say its the slave.   Stop and go traffic it was being used a lot and the piston seized then un-seized.  Take it apart. I bet 20 bucks its full of crud. 78k miles he said.
Normally I'd agree with you, but on mine one of the earlier steps was to replace the slave cylinder with a billet aftermarket one (http://www.oberon-performance.co.uk/acatalog/Kawasaki_Clutch_Slave_Cylinders.html)and I still had the problem after I fitted that. My OEM slave wasn't that crudded up either when I took it off.
Regular cleaning of the master cylinder is also needed and I use a piece of very fine stiff wire to clean out the return hole in the master. It's not the best design of clutch master/slave I've seen, and seems to be prone to issues given what I have seen on many of the other Kawasaki forums (it's used on LOTS of Kawasaki's).
George "Boomer" Garratt
Wickford, UK