2010 TC250 Clutch Question

[Henner Mx]

Ive read about this in the magazine articles and it happen to me yesterday. When going over a jump and just before landing you give the bike throttle and i could feel the clutch lever just go right away for a few seconds and then its fine again it only seems to do it in the air at the panic rev stage. Any thaughts or opinions would be great Thanks.

 

[krieg]

Ive read about this in the magazine articles and it happen to me yesterday. When going over a jump and just before landing you give the bike throttle and i could feel the clutch lever just go right away for a few seconds and then its fine again it only seems to do it in the air at the panic rev stage. Any thaughts or opinions would be great Thanks.

Cody has complained about the exact same issue. When I was riding the bike in the woods (prior to him taking it over as his race bike), I never noticed it. I never really believed him until I read this. I've bled the system twice since he first complained but he says it's still doing it but only occassionally and very briefly... Hmmmm.

 

[Henner Mx]

Yes is very brief im talkin seconds but it only seems to happen when the rear tire is not touching the ground and the throttle is pinned over jumps or threw whoops or choppy sections. I can live with it although annoying at times not a huge issues just wondering why and if theres a fix, bleeding is definetly not the problem as ive done a dozen times now with no good results.

 

[Henner Mx]

It is the exact same thing that was stated in the test motocross action did on this bike.

 

[Motosportz]

On jumps and in whoops? Maybe it is related to the master cylinder and the fluid bouncing up allowing a little bubble for a second. I can't think of anything else that would do that in those conditions.

 

[krieg]

On jumps and in whoops? Maybe it is related to the master cylinder and the fluid bouncing up allowing a little bubble for a second. I can't think of anything else that would do that in those conditions.

That's exactly what I thought. When I bled the last time, I overfilled the reservoir to check this theory. Unfotunately, we haven't raced since then. I'll report back.

 

[Henner Mx]

No not because of the bumps lets see if i can explain a little better. Ok where i rode yesterday there is a 75ft up hill step up that you can hold it 4th gear pinned up to it and the landing is deep sand just just before landing you hold the bike wide open to keep forward momentum but for those few seconds in the air when its wide open is when it does it and because i always have my fingers on the lever i can feel it just come right to the bar very strange but by no means because of bumps just when the rear tires in the air and the bike is wide open. Hope that explains a little better.

 

[ScottyR]

I have a customer complaining of the same issue with his TC250.

 

[wally111]

My son complained aswell, and I did feel it myself.
I thought is was the heat from the exhaust pipe boiling the fluid, i realigned the hydraulic cable further away from the heat source, it seems to have helped.

 

[mxer74]

I can also attest to this. I know almost every single moto I've raced in this year, I have the clutch fade on me a couple times each moto. Granted, I'm not doing a 2 hour HS but for the 6-8 laps I'm racing per moto, I'd like to think I'm on it pretty hard . We've tried the bleeding thing with no luck either. I think it's just a habit of this Brembo system because I've never had a Magura system do this to me. I've gotten use to it by now and it doesn't surprise any more, but still odd. Very intermitent, might only loose it for 2-3 corners then it will be back to full power the rest of the moto......strange. Thought I'd share. Have a good weekend everyone!

Blake

 

[krieg]

I can also attest to this. I know almost every single moto I've raced in this year, I have the clutch fade on me a couple times each moto. Granted, I'm not doing a 2 hour HS but for the 6-8 laps I'm racing per moto, I'd like to think I'm on it pretty hard . We've tried the bleeding thing with no luck either. I think it's just a habit of this Brembo system because I've never had a Magura system do this to me. I've gotten use to it by now and it doesn't surprise any more, but still odd. Very intermitent, might only loose it for 2-3 corners then it will be back to full power the rest of the moto......strange. Thought I'd share. Have a good weekend everyone!

Blake

Thanks for sharing Blake. Now I know Cody wasn't making it up. I'm really starting to wonder if there's anything to the boiling theory. The line and slave cylinder are pretty close to the pipe. I may try insulating the line and shielding the slave.

 

[ScottyR]

I think it is the Brembo system. If you take a look at the Factory KTM guys bikes they all are using the "old" Magura master cylinders even though the production bikes are coming with Brembos.

 

[wally111]

We are now a Month further and I would like to know How everyone solved the problem, after I realigned the clutch cable away from the exhaust , we had no more clutch fade, anyone else had the same result, or came up with a different solution?

 

[ghte]

Interesting Scotty that the KTM boys are using the Magura.

 

[Henner Mx]

I moved mine away from the exhaust as well but still does it i have just been living with it and i just baught a new husky cr125 that i have been riding more than the tc but the tc has 51.5 hours with no problems otherwise.

 

[BILLF]

soft clutch

We have had this same problems on some Aprillia road race bikes under full power then shut off they would loose clutch pressure for a few seconds at the lever,they also have Brembo master cylinder,so we went to after market billet set up and even after market slave ,still did it.,we never did get it cured.We have a oil pressure theory inside the mainshaft pushing in the slave cylinder a bit ? it seems crazy but we have thought about putting a couple notches on the clutch throw out to let some oil slip by it .After pulling our hair out with the Aprillia the man crashed it and we never got a chance to test our fix.billf

 

[Motosportz]

Never had this issue on my 2010 TXC250.

 

[robertaccio]

I am going a little out on limb,,,but the GP motorcycles AMA US supermoto team bikes (not your X-Lite motors of course) and FIM SM machines had odd problems with clutch push rod high RPM vibration (450-510s) that caused similar strange issues on the AMA SM machines.
The Team started to put an o-ring onto the shaft near the Slave cylinder end to dampen the vibes on the shaft. I have done the same to my TXC450 although I have never had the stated problem with my clutch (but I have had many other issues!!). This may be a helper for the above issues or at least an aid for the system as well.


PS thought, could crankcase pressure at high RPM actually push the slave piston back into the cylinder?? I know we have breathers to keep the pressure down, but?? possible? So when you squeeze the lever you have dead space between the push rod and piston.
PPS this issue above actually was doing this to the slave piston, the vibe bounced the rod against the piston and had it push back into the cylinder (that was theory anyway that appeared to cured with the oring mod)

 

[nicogc]

hi all,
i am having this same problem with a TXC510 2010. i would like to know if any of you found a cure, or if the oring mod helped.
has there been any info from the factory or a dealer on this issue??

thanks for any help you can give me********************************************************************************!