Clutch slave cylinder issue again 135K (education + photos)

[~TABASCO~]

Hello,

Here is an issue I have run into again and might help someone else. This bike has 135K miles and the clutch lever pull did not feel normal. I checked the fluid and it was dark. It would be best to install a rebuild kit in the top reservoir. Once I did this and pumped though new fluid it cleaned up but kept pumping a ton of air out the slave cylinder. After quite some time I realized I have seen this issue before and I stopped pumping the new fluid thought the system. I pulled the slave cylinder because the first time I came across this we came across the lower seal being hard and the piston wearing cockeyed in the bore. I removed this slave cylinder on this bike and pulled a bit on the piston and it almost just fell out. Thats not suppose to do that because of the friction of the rubber seal. Once it came out you can clearly see its wearing strange and the seal is giving up. The dust seal also shows that it has been weeping. With the new slave it will be fixed up.
I thought I would pass along this info incase people have issues with their clutch. I suggest folks flush the clutch once a year and keep the fluid lucid. I also noticed on both bikes that the upper aluminum piston has worn and it appears that there is "aluminum" in the upper reservoir. Im thinking this junk along with the old fluid, flowing down to the lower cylinder has partially caused the slave to fail. Probably another good reason to throw a rebuild kit in the upper reservoir once and awhile, they are about $20.


(On the piston you can see wear at the top right and lower left. I believe when its in the actual cylinder it would be rear top / front lower, binding. )

Might be all useful information for someone in the future. If / when someone might need a new slave cylinder you can try and find a stock one from a parts house. If you don't know, you can find an aftermarket unit from "Off De Road" German motorcycle website and have one from Germany in about 3-4 days.



(Inside view of the slave dust seal)


(Inside bore)


(Slave piston 135K miles)

 

[sky4]

you've inspired me to change my clutch fluid this year. did it last year. it wasn't "bad" but it was rougher than the brake fluid. Makes sense though, clutch gets pulled hundreds of times a ride.

 

[~TABASCO~]

Update: I installed the new slave cylinder and got the air all out of the new cylinder and everything works perfect. The whole system works as intended and is as good as new. If you run into this issue start with new fluid and an upper re build kit. If your still having issues its more than likely the lower portion.

 

[jwrands]

I just ran into the same problem of not being able to get all the air out of the slave. I used the bleeding technique as described in the shop manual. I went through half a bottle of DOT4 before I realized something must be up! I suspect air is getting sucked in passed the slave cylinder seal during step h when the lever is released. I was eventually able to get the air out by letting the fluid flow freely out the bleed screw (not under pressure). I guess bleeding without pressure doesn't work as well, but it is the only way I can prevent air from getting sucked back in.



@~TABASCO~, can the slave cylinder be disassembled for inspection/cleaning, and put back together with the same parts? It's a shame the slave wasn't designed to be rebuilt.

My clutch lever goes all the way to the grip. Is that normal on this bike? It's hard to feel if the system is properly bled since the lever doesn't stop before the grip like the brake lever.

 

[~TABASCO~]

I just ran into the same problem of not being able to get all the air out of the slave. I used the bleeding technique as described in the shop manual. I went through half a bottle of DOT4 before I realized something must be up! I suspect air is getting sucked in passed the slave cylinder seal during step h when the lever is released. I was eventually able to get the air out by letting the fluid flow freely out the bleed screw (not under pressure). I guess bleeding without pressure doesn't work as well, but it is the only way I can prevent air from getting sucked back in.

View attachment 90191

@~TABASCO~, can the slave cylinder be disassembled for inspection/cleaning, and put back together with the same parts? It's a shame the slave wasn't designed to be rebuilt.

My clutch lever goes all the way to the grip. Is that normal on this bike? It's hard to feel if the system is properly bled since the lever doesn't stop before the grip like the brake lever.

Yes, you can pull it apart. If your sucking in air, more than likely it’s ‘done’, take a look but it will probably need to be replaced. The issues I’ve come across are both with bikes with 135K.
Yamaha does not sell a rebuild kit. Someone in the world might have the parts. For general safety, one ordered the stock unit, the other ordered the German unit. The German unit can be rebuilt.
The lever can be brought back to the grip. I would check for air again. That seal does not typically “fix itself”.

 

[jwrands]

Just found out that All Balls now sells a rebuild kit for the S10 clutch slave cylinder. Figured I'd give it a try before replacing the whole assembly.
Check it out here https://www.allballsracing.com/18-6035.html

Kit comes with the piston seal and engine side push rod seal, but oddly no dust boot.

I just rebuilt my slave with the new piston seal, and it seems to have solved my leak.

Check out the difference between the old seal and new seal. (new on the right)


new seal installed


old seal installed

 

[~TABASCO~]

Great idea before maybe it started leaking / weeping......

 

[RCinNC]

It's weird that the slave can't be rebuilt with an OEM rebuild kit, when you can get parts to rebuild a master cylinder and brake calipers. The caliper is the same principle as the slave, the piston just pushes on the brake pad instead of the clutch actuating rod.

Tabasco, I'm curious...when you found that the piston got cockeyed inside the cylinder, do you think it damaged either surface enough that it would have interfered with the seal being able to function properly? Or would the damage on the piston or cylinder cause premature seal wear to a replacement seal? I'm at 102,000 miles on my original slave, and I've never taken it off. I've noticed that the clutch engagement point seems to be a little further out from the grip than it used to be, though there's no clutch slippage or anything, I just wondered if a slave with 100,000 plus miles was worth rebuilding, or if it would be more prudent to just spring for the $113.00 replacement OEM slave and have fresh new surfaces on the piston and cylinder.

 

[WJBertrand]

Curious about impressions regarding the German replacement slave cylinder. Has anyone used one and noticed an advantage or improvement?

 

[RCinNC]

I checked out the price of the Off The Road slave cylinder, and it's actually a pretty good deal compared to OEM. The Off The Road one is 119.95 Euros, which translates to $130.10 US. The OEM slave is $113.00 from Rocky Mountain ATV. However, the Off The Road price includes shipping and VAT, and non-EU customers don't have to pay VAT, which amounts to about 19%. If you factor out the VAT, it looks like the aftermarket slave cylinder would be about $97.16, shipped. No idea how long shipping currently takes from Germany; Off The Road's home page has an announcement about supply chain issues and shipping delays due to Covid-19.

Clutch slave cylinder Yamaha XT-1200Z Super Tenere

CNC machined billet clutch slave cylinder Yamaha XT-1200Z Super Tenere For more than 20 years now Ducati owners trust the well known and famous…

www.off-the-road.de

I bookmarked the page for later.

 

[jwrands]

Curious about impressions regarding the German replacement slave cylinder. Has anyone used one and noticed an advantage or improvement?

Did you forget?

New Oberon clutch slaves

Just received this through from Oberon. No good the s10 but I know many of you have FJRs too They have plans to produce one for the s10 but we’ll have to wait a bit longer. Sent from my iPhone using Tapatalk

yamahasupertenere.com

Sounds it's only a minor difference in providing a lighter pull. Maybe you'll just have to go for it and let everyone know how it works for you. I never felt like the clutch was dragging. Try running the bike in gear on the center stand so you can see exactly where the clutch friction zone is. The wheel will still turn with the clutch pulled in because some power will be transmitted through the oil.

 

[thughes317]

Try running the bike in gear on the center stand so you can see exactly where the clutch friction zone is. The wheel will still turn with the clutch pulled in because some power will be transmitted through the oil.

And it'll sound like all hell is breaking loose because of the extreme angle on the U-Joints. Just an FYI......

 

[WJBertrand]

Did you forget?

New Oberon clutch slaves

Just received this through from Oberon. No good the s10 but I know many of you have FJRs too They have plans to produce one for the s10 but we’ll have to wait a bit longer. Sent from my iPhone using Tapatalk

yamahasupertenere.com

Sounds it's only a minor difference in providing a lighter pull. Maybe you'll just have to go for it and let everyone know how it works for you. I never felt like the clutch was dragging. Try running the bike in gear on the center stand so you can see exactly where the clutch friction zone is. The wheel will still turn with the clutch pulled in because some power will be transmitted through the oil.

Either I forgot or I didn’t know the Oberon and German slaves were one and the same.

 

[bimota]

been running the german one for 3 years now defenetly a lighter pull

 

[Tenforeplay]

Does the clutch engagement normally engage pretty quick? I have no problem putting it into gear at a standstill, no gear grinding. The engagement seems pretty quick when the lever is releasing and I don't see any way to adjust that. Does the lever distance number from bar change engagement amount? I am on No. 4 which I think is closest to bar but I was thinking this didn't make any difference what number is adjusted to.

 

[Cycledude]

Does the clutch engagement normally engage pretty quick? I have no problem putting it into gear at a standstill, no gear grinding. The engagement seems pretty quick when the lever is releasing and I don't see any way to adjust that. Does the lever distance number from bar change engagement amount? I am on No. 4 which I think is closest to bar but I was thinking this didn't make any difference what number is adjusted to.

That’s a good question, seems like they have spent quite a bit of time and money making these adjustments easy but for me they don’t seem to make any noticeable difference, maybe they make more of a difference for people with small hands ?

 

[Tenforeplay]

That’s a good question, seems like they have spent quite a bit of time and money making these adjustments easy but for me they don’t seem to make any noticeable difference, maybe they make more of a difference for people with small hands ?

That's the weird part. I wear xl or xxl gloves and I think it is adjusted closest to the bars. To put it at the smallest number puts them way out there. I guess it is what part of the fingers a person uses. My clutch starts to engage as soon as the lever comes off the bar. I was wondering if that was early or normal. Though everything works fine.

 

[scott123007]

The lower the number on the lever, the further out the lever is from the handlebar when the clutch engages. It may be hard to notice much difference, but there is. There is no other adjustment you can make to change the engagement point. There may be minor differences in engagement points between one bike and another due to tolerances that can not be adjusted, just like differences in brake lever movement engagement points. "Most" of these differences have to do with the condition of the caliper piston sealing ring or seal in the slave or master cylinder.

 

[MattR]

Either I forgot or I didn’t know the Oberon and German slaves were one and the same.

They’re not. Oberon is British. But they still haven’t started producing slaves for the S10


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