Clutch help!

[juddspaintballs]

I have the Magura master cylinder. It takes mineral oil, but I read in several places that fork oil or transmission fluid also worked just fine.

[anotherguy]

I've seen a lot of aftermarket levers cause issues with brakes/clutches. They fail to leave any free play and it heats up the plates/rotors to the point of failure. Replace with the OEM lever and see if the problem subsides. There must be free play.

[thetable]

Just don't use grocery store mineral oil. It's WAY too thick for any fine modulation.

[juddspaintballs]

I think I have it all sorted now. I borrowed a 450 EXC from thetable with a known good master and slave cylinder setup. I removed the master cylinder, slave cylinder, and hydraulic line without breaking the system so it remained as one working unit. I put it on my bike. No change on my bike. His bike is a little difficult to roll in gear with the clutch in. I put both bikes back together.

Knowing that my master/slave setup wasn't the issue, I flipped the bike to it's left side and started pulling the clutch again.

I think I found the problem:



And after 2 hours with a fine file and sand paper, it looks like this now:


I also did the same for the inner hub the metals ride on. I reassembled the clutch and put it all back together. Everything works as it should now. Slight resistance rolling the cold bike in gear with the clutch lever in, but it doesn't try to turn my motor over anymore. I can kick it in gear without lurching forward. It doesn't bog down when stopping in gear. Whoohoo!

Prior to finding and fixing the issue, I already ordered a new clutch pack and springs, slave cylinder, master cylinder rebuild, and hydraulic line. If my trip weren't so soon, I'd cancel the order, but at this point it's better to have them on hand than to not have them around.

[Bucho]

Glad you got it sorted out. We will give it a good workout next week

[Rut Row]

is that normal wear? what caused it?

[Space Ghost]

Yeah I think your right. Magura uses mineral oil. Brembo uses brake fluid.

[Boom Boom]

is that normal wear? what caused it?

Yes, fairly common.
To make a smoother clutch on the trials bikes it is common to take the plates and file the surface that makes contact with the basket to a flat even surface...stock they are not in a machines flat condition and as you can see from the basket the face of the plate will wear into the basket and cause it to stick and not slip free.
The basket in my GG enduro was not looking the best so it was replace with a Rekluse basket that had far more meat in the basket and alum seemed to be of a higher grade. The file smooth trick works about once and then you start getting too much slop and the basket will need replaced or tolerate a sticky clutch.
If you look on trials central it is called the "Beta clutch fix".

Glad you got it sorted out but for the extra cost of the proper fluid suggested for your clutch...I would swap out to the suggest oil. It is like water and what you are using has to be thicker, just nothing I felt the cost savings was worth the risk of not working as well.

[juddspaintballs]

I sucked it up and bought a new inner hub and clutch basket. Everything is set to arrive on Wednesday. It's cutting it close, but it looks like I'm going to H&M with an entirely new clutch system...literally everything replaced but the push rod between the slave and pressure plate. Can't take any chances on a bad clutch ruining my trip.

thetable has provided me with some Magura blood.

Oh yeah, I'm now a "frequent buyer" at RMATV level Silver. It only took 3 days of shopping...

[Boom Boom]

Welcome to KTM ownership....Keeps Taking Money.