Magura clutch for YZ250

[slodad]

My son bought at '98 YZ250 that came with a Magura hudraulic clutch installed. We replaced it with the stock cable setup because the clutch would not disengage. With the Magura, there was very little movement of the clutch actuator arm. It turned out that reinstalling the cable unit was not the solution, but before putting back the Magura, I want to make sure that it is operating properly.

The Magura clutch lever had only a few degrees of travel before stopping, unlike the cable system that can be pulled all the way to the handlebar. Is that normal, or should it travel over a greater range? The slave unit rod that attaches to the clutch actuator arm has only about 1/8" of travel, compared to about 1/2" for the cable. Should that be enough to disengage the clutch?

I removed the cap from the slave unit, and seeing a hex socket in the actuator piston, assumed that there might be some adjustment potential there. What I found was the opportunity (of which I took full advantage) to remove the piston and totally mess up things by introducing lots of air into the system when replacing the piston.

So now the questions are: 1) does one need special Magura tools for bleeding the system; 2) how does the Magura system normally feel, lever travelwise; 3) is 1/8" of travel all that should be expected from the slave unit; 4) should that amount of travel be sufficient to disengage the clutch?

 

[Rcannon]

The problem is not with your hyd. clutch or clutch cable. The older yz's start to develop clutch problems.

To make a long story short, I ended up solving mine by using a valve spacer from one of the 250f bikes. I believe I used a thickness of 3mm (or something close). The rod that runs through the case gets slightly shorter after use. The shim is placed inside of the bearing/guide assembly where it touches the pressure plate. This changes the overall length of the push rod. http://www.yamaha-motor.com/sport/parts/home.aspx Go the 98 yz 250 parts diagram for the clutch.

Look on the outside of your case. The push lever (piece 24) in the Yamaha breakdown starts working at a really bad angle to for the clutch. Eventually the lever moves but really does not move the rod. The 3mm shim will have it working like brand new. I have used my shim for over a year without problems. The 250 f sized valve shims will drop right in place (inside piece number 19).

 

[slodad]

The clutch itself is not the issue now. The clutch does function correctly, after a new basket and a bit of attention to the clutch plates, However, the cable system is still in place and I'm curious whether the Magura will provide the range of movement necessary to disengage the clutch. Also, I still need to know how one bleeds the Magura system and whether it is performing normally. I suppose I could go to a KTM store and see what theirs do, but I was hoping for some guidance rather having to hop into the car.

 

[Rcannon]

I have looked at the magura clutch, mounted on the ktm's, and I think it will work. I almost bought one fo rmy bike, but backed out at the last moment (or wife found out).

My first thought is to improve the leverage on the clutch. Once that rod wears, or shortens, a lot of movement at the lever does almost nothing to the clutch.