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Discussion Starter #1
Hi all! This is my first forum post, so go easy on me! :)

I have a 2004 KTM 625 SMC, and I've had a recurring problem with it. After it sits for a while, the clutch acts great. However, as I ride it and use it, the engagement (disengagement?) point will change. It goes from being a normal clutch, fully extended, to being soft almost all the way to the bar.

I just took it to a local KTM shop and had them look at it. They bled the clutch and also made sure the plates weren't too worn. I live about an hour away, so I went to pick it up, felt the clutch and thought everything was fixed. I rode it home, and about 30 minutes down the road, the problem returned.

I'm almost pulling my hair out with this issue, and don't know what else to do!

Any insight at all would be majorly appreciated guys.

Thanks!
 

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Used to have similar problems on my built 565cc RFS motor.

First thought is you need Magura Blood. The real deal fluid. However if it's all been changed and you still have problems... might need to throw a part or two at it.

You could go with a much better aftermarket slave cylinder. These Oberon slaves are waaaaaaaaaaaaay better than stock.



The OE unit is a single O-ring design. This means as the cylinder goes back and forth with pressure it can and does rock from side to side. This lateral motion eventually wears the cylinder walls and adds resistance.

The Oberon slaves use U-ring seals, 2 of them. This eliminates the side to side by keeping the cylinder straight and true, the U-rings essentially provide 4 ring seals as opposed to just one.

The feel is night and day. Remember the first time you rode a moto with a hydro clutch compared to cable clutch? It's like that all over again. What you thought was buttery, is actually gritty and squishy.

Another thing to consider is the master, I got rid of the stock lever Magura model 163 (9.5mm). It had over 12 years and 20k of use and abuse. In the last 2 years I swapped the seal kit 3 times and still had a spongy lever.


I ended upgrading to the Magura model 167 (10.5mm), it's basically the same just has a larger bore to move more fluid and improve feel. I was thinking about a radial master (14-16mm) but they cost 2x as much.


Swapping both of these killed my issues and I haven't had any problems since.

Good luck getting yours sorted.
 

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Discussion Starter #3
Thanks for the reply. I will look into those parts. I contacted the shop that did the work and I will ask them if they went through the steps you mentioned.

I'm glad you got your problem sorted out; I hope your information can help fix mine too!
 

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Another thing you may want to consider is high oil pressure.

If you have a bit too much oil in the case, the pressure may be enough to push back on the slave resulting in spongy lever syndrome. It feels tits while cold and for the first 20-30 mins, then goes limp with heat and high revs.

http://www.ktmatvhq.com/forum/xc-engine-carb-drivetrain/12938-oil-mod-clutch.html
http://www.ktmforums.com/forums/offroad-competition-rfs/1881-ktm-400-exc-clutch-pressure-problem.html
http://husaberg.org/mechanical/14572-clutch-problems-2010-390-a.html

Might need to peel the plastic seal off the bearing behind the clutch slave.
 

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I just got an oberon slave a couple months ago, and it is very nice. Also bought a oem master because the cylinder walls were all corroded, and got air in the system all the time. Then had bad clutch drag from warped clutch plates, so threw a new clutch in it. All of this was in about two weeks, so I feel your pain on clutch issues.
 
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