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Is my clutch slave jammed?

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Trying to resolve a slipping clutch problem.  Several weeks back I had chain break, it wrapped around the sprocket and jammed into the clutch slave.  I took the clutch slave off and I'm wondering if it is jammed.  If I push the ball bearing it will not move at all.  Should I be able to push on the bearing and get some movement? Or is the entire piston supposed to move? 

Bike is a 2008 KTM EXCR 530

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The entire piston should move but it takes a lot of force.  Do not squeeze the lever with the slave off as you can generate enough force to blow the snap ring groove apart.

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Mine is a 2008 so its different than the assembly on the new bikes.  Mine does not have a snap ring at the top holding the assembly together. I took the slave off the hose.  Should I be able to compress the ball in by hand?  I put a small C clamp on and tightened it, it just seems like its way to tight, does not feel or look like its compressing.  

 

Does anyone know how this comes apart?

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Edited by Bill_B

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I looked at the parts fische, no snap ring or locking device. I would use a penetrating oil to get the piston moving- maybe even a heat gun figuring you can salvage the housing and replace the piston. Sounds like it's seized in the AL slave housing. 

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Figured out what the problem was and I'm posting this in case anyone runs into the same issue.  The piston was jamming pretty bad. 

I bolted the slave back on the hose but not to the motor, bleed the line.  Pumped the clutch lever to see if it will move when activating the clutch lever.  As I pumped the lever the piston gradually moves outward with each pump of the lever. SO I guess its working and yes it takes a lot of force.  After the piston was out a bit I then pushed the piston back in manually.  

I decided to disassemble the slave it to see whats inside. I could not find anything on the internet to clearly show what the parts are.  Only the OEM microfiche at part suppliers but hard to see the parts clearly.  I used compressor hose to pump air in and the cylinder pops out with great force.  Like uncorking a bottle of champagne IF you do this make sure you put slave into a baggie or wrap it in towels, it will make a mess.  

As a result of the chain slamming into the slave cylinder, it dented the side wall of the slave housing.  At first, I thought there is no way there is internal damage. BUT to my surprise, the wall thickness in that area is not that thick so it has created a dent in the side wall the and into the end of the piston. It has caused pretty major functional damage and the piston was jammed as a result of this.  See pics.  

I tried to fix this by machining out the indented wall and OD of the piston shaft but I just can not get the piston to move in and out freely without binding.  I can get the piston to move in and out pretty good in one orientation but if I rotate the piston it will jam up.  So there may be some issues with the concentricity of the pocket where the end of the piston goes into the pocket. The measurements indicate everything is concentric (round) BUT the piston will not freely move in and out in any operation or rotation. So the piston and slave housing need to be replaced.  

Yaaaa! spend more money$$$ on bike parts.  

OH and now its time to buy and install a clutch slave guard! 

Like a dumb ass I ended up replacing the clutch pack before investigating this, I know it was a backward approach. I should have taken the slave off FIRST but I just kept looking at it thinking "how could there be anything wrong? DUH

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15 hours ago, Bill_B said:

Mine is a 2008 so its different than the assembly on the new bikes.  Mine does not have a snap ring at the top holding the assembly together. I took the slave off the hose.  Should I be able to compress the ball in by hand?  I put a small C clamp on and tightened it, it just seems like its way to tight, does not feel or look like its compressing.  

 

Does anyone know how this comes apart?

IMG_0956.JPG

Guess I should've paid more attention.  I didn't see you had an '08.

Anyway, good analysis and writeup on your findings.

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Never used the guards because I only run the chain several thousand miles for strict dirt use and replace it. Lots of riders get more out of the chain and guards will help. At high speed sometimes they couldn't even get the chain off the bike it wrapped so hard around the counter. 

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If running (Non press) side plate masters , this type of failure can easily happen.

 

and looks like what happeded here

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I do not see the top chain knock down bar. There should be an aluminum piece that goes right over the top of the front sprocket to prevent the chain from wrapping up like yours did. No after market slave guard needed if use this stock part.

 

Its called a chain damper by KTM

 

 

Edited by Mike in Fresno
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Bill_B,  glad you found it and shared the info.  Be glad that it was that simple and Cheap!  Smile when you ride next.

I had one do that at high speed, the engine came to such an abrupt halt it shredded half of the gears in the transmission! That was Not cheap!

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14 hours ago, eric33 said:

Bill_B,  glad you found it and shared the info.  Be glad that it was that simple and Cheap!  Smile when you ride next.

I had one do that at high speed, the engine came to such an abrupt halt it shredded half of the gears in the transmission! That was Not cheap!

That sucks I got off easy I guess.  I may invest in a chain press in the future and go with the rivet master link. 

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On 3/16/2018 at 11:30 AM, Mike in Fresno said:

I do not see the top chain knock down bar. There should be an aluminum piece that goes right over the top of the front sprocket to prevent the chain from wrapping up like yours did. No after market slave guard needed if use this stock part.

Its called a chain damper by KTM

3

Actually, I'm pretty sure I had that part on my bike but a while back I took the sprocket guard off and the peace you're describing at the same time to do some other work on the bike. Then my bike sat for several weeks during summer "no riding" with the guard off and the peace got shuffled around on my work table.  Totally forgot about it for a while and then found the part floating around on my table, but then I could not remember where it was mounted and just never got it back on the bike.  I was going to post and ask but never did,  Anyone know were it goes and how it is mounted? 

 

Heres a picture of the part is this what you're talking about?

 

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Edited by Bill_B

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