KTM hydraulic clutches

[Rot Box]

Since a lot of you guys are drinking the orange stuff I figured I'd pick your brains. A friend is having me do some repairs on his 06 KTM 400EXC over the next couple of days. He says the hydraulic clutch quits working shortly after he bleeds it. He said during the last ride it worked fine for around ten minutes then stopped. Not sure it it's loosing fluid or not.

I understand how they work I'm just wondering if they are known to have issues or if there's anything in particular that I should look at or upgrade? Recommended fluid? Off the top of my head I'm thinking either it's pulling in air somehow or the slave or master cylinder needs rebuilt. I have a vacuum brake bleeder that I've used a lot on brakes and automotive clutches---is there a better method to use? I poked around on youtube but didn't find a lot. Thanks for any advice.

Andrew

 

[Tonkaman]

Jeeper just had this exact problem with his bike and there were 2 problems.
Problem 1- the ktm guys told him he had to run Magura Blood but the clutch is designer for DOT 4. The wrong fluid caused all of the orings and gaskets to swell and leak.
Problem 2- His slave cylinder would cycle as it should buy it was really stiff. He got a new slave cylinder that moved much smoother and easier solving the problem

 

[ricsrx]

Jeeper just had this exact problem with his bike

Crazy how it would work monetarily then stop working.....

 

[Rot Box]

Thanks

I pulled it in the shop today. It was not working at all until I pumped it about 12 times then it built pressure and started working again. I wonder if KTM changed their fluid requirements at some point. This one says mineral oil only on the master cylinder cap

 

[jeeper]

There is a Brembo? brand and a Magura brand clutch.. There is a little symbol on the top of the res to tell you what you have... If the cap says to use mineral oil, then you need the Magura blood. The other will say DOT 4-5.1.

Use a syringe and back flow the fluid through the slave up to the master, and it will be fine, no further work needed. If you have the slave off you can push the piston in and out until you have no air bubbling out the master.

The rebuild kit is not too hard to do.. but most likely you just have air in the system.

 

[Rot Box]

Great thanks! I popped off the slave cylinder and back bled it. Pushed some bubbles out so hopefully that will take care of it. No signs of leaking or anything. It's the Magura setup.

 

[Rot Box]

Ugh. I found the problem.. The slave cylinder piston wore a nasty groove in the housing--crappy design if you ask me. I also noticed the hose was leaking under full pressure $144 for the slave, $65 for the hose and it should be back in business.