KTM 525 Clutch

[warhammer]

We're running an '08 KTM 525 in our car, and we've been having some issues with our clutch. The service manual specifies SAE 10 hydraulic oil for the clutch, but this oil keeps screwing up the master cylinder that we've been using. I think the seals in the master cylinder are absorbing the oil, expanding and then getting stuck. So, has anyone used a different kind of fluid in their clutch (like brake fluid), or used a master cylinder that can take this SAE 10 oil? Thanks

Dave
Zoomie Racing

[warhammer]

We're running an '08 KTM 525 in our car, and we've been having some issues with our clutch. The service manual specifies SAE 10 hydraulic oil for the clutch, but this oil keeps screwing up the master cylinder that we've been using. I think the seals in the master cylinder are absorbing the oil, expanding and then getting stuck. So, has anyone used a different kind of fluid in their clutch (like brake fluid), or used a master cylinder that can take this SAE 10 oil? Thanks

Dave
Zoomie Racing

[oz_olly]

Is your SAE 10 a mineral oil or synthetic oil? Switching from mineral to synthetic or vice versa may help. Worst case you could see if there is a genuine KTM oil, if that isn't compatible with the seals then there is something pretty wrong.

On another note it's good to see another military academy getting in on the forum (I went to the Australian Defence Force Academy).I have a friend who is visiting USAF Academy right now. I told him to hunt down the FSAE team and have a look. Do you have a team website? I did a bit of googling but didn't find you. I have seen photos of the Naval Academy car from a couple of years ago. Is there much rivalry between the various academies at competition?

Cheers

Olly

ACME Racing
UNSW@ADFA

[warhammer]

The SAE 10 is a mineral based oil...I checked with KTM and with Tilton (the master cylinder manufacturer) yesterday and the KTM clutch/slave cylinder apparently needs a mineral-oil based fluid, while Tilton said that will burn up their master cylinders. On a side, before we found out that we were supposed to run mineral oil in the clutch, we ran dot 4 brake fluid for a couple weeks and it didn't seem to hurt anything, but KTM swears it will mess their clutch up.

Ha ha, yeah there's a bunch of Aussies running around here right now, I haven't seen your buddy yet but I'm sure he'll find us eventually. We don't have a website yet, we're still just focusing on trying to finish endurance this year...

Dave
Zoomie Racing

[benny41]

im pretty sure we have run brake fluid in our 04' model clutch for years and it hasnt really given us any trouble.

Ill check when i head into the workshop tomorrow

[warhammer]

I finally got ahold of Tilton and a couple of Polaris dealerships and it looks like the seals in the slave cylinder don't work with brake fluid - they swell up causing the piston to stick in the slave. But, pretty much any automotive master cylinder you can buy won't work with the mineral oil that the bike systems run on, for the same reason. So...we're getting some different o-rings for the slave that should work with the brake fluid, and in the meantime we're switching out seals in the slave every few days

[MikeDutsa]

watch the travel of your slave cylinder, it is easy to push your clutch basket to far with those motors, allowing the outer friction plate to come out of the basket. just a heads up from experience......

[warhammer]

Yeah, that just happened to us too. We had to pull the clutch apart to fix that, then we put a positive stop on the clutch pedal travel to keep that from happening again

[MikeDutsa]

we just bled some fluid out of the master cylinder so that it would bottom out before the slave would go to far.