450 Clutch problem
 

I replaced the fiber plates on my 03 FSE, everthing went fine, I thought. I blead about a 1/4 can of new dot4 fluid through the system. The clutch had full resistance, felt fine. Started the bike let it warm for a minute, pulled the clutch lever, and there was no resistance, nothing. Shut the bike off to bleed the system more, and there was full resistance again?? I've now bleed more than a 1/2 can of fluid, and I get full a full stream of fluid each lever pull, no bubbles. Now the clutch works while the bike idles, but goes away during the shift to second, no resistance at all, let the bike idle, and the clutch comes back. :confused:
I'm thinking the traditional bleeding sequence is not working for hydraulic clutches. Is air causing this, if so, how much air and where is the air hiding?
Anybody else have this problem with hydro clutches?

there should also be a adjustment in addition to bleeding it, also make sure your slave cylinder is not bypassing and not holding pressure, but it sounds like to me that you have some clutch dragging, and it may be fine when idling(motor not pulling) and when shifting revving the motor it drags and is not fully disengaging.

Like it was mentioned, make sure your lever adjustment is backed off fully.
Bleed from the bottom to the top with a hose and syringe. That is the only way to be sure you get all the air out....

You will find that the piston on your slave cylinder is being pushed back.
Two things can cause this. Running to thick an engine oil. (should be 10w40)
or the spring behind the piston on the slave cylinder is to week.
Gas Gas updated this spring in late 2004 to a heaver spring.
I bet if you take your master cylinder cap off start the bike and rev it you will see fluid being forced up, because the piston is getting pushed back.
If the engine oil is to thick a grade it builds to much pressure down the main shaft and pushes the piston back.

Note: If you purchase a new slave cylinder kit is is the two stroke part number and has a weeker spring in it so you will need the updated spring to go with the kit.

Thanks for the replys. :D
The clutch works fine while the motor is not running, so it's not a lever adjustment or drag problem. It has less drag now with new plates than with the old plates.
I use Rotella 10-40. I had the resesovir cap off the whole time I was bleeding, running and not running, and got no blow back. I will check the slave unit spring.
It's got to be air in the system, but you'd think after 10-12 oz of new fluid the air would be gone. I'll borrow a vacuum type bleeder.

Trust me I know the heaver spring will fix it.

i am not up fully on gasser cluthes but my experience with cannondale hydraulic clutches they only reccomend a mineral oil something like magura blood I thinks its called i run a hyd clutch oil mineral oil in the ones I have the clutch oil is not much thicker than brake fluid it may be too thick and not flowing through the lines properly.

Gasser clutch hydraulics use brake fluid not mineral oil, always check the top of the master cylinder to confirm..

[QUOTE=Sandman;11140]Trust me I know the heaver spring will fix it.


Sandman,
I can't see a spring clearly in the exploded drawing of the slave unit, and have not taken mine apart yet. I haven't located a rebuild kit.
What does that spring do?
Does it control a check valve?
If it's a check valve spring, I could see, under engine vibration allowing the fluid to bleed back to the reservoir.

The spring is behind the piston in the slave cylinder.
The books are crap and may not show it.
I will try and find the part number you will need, because it is not the one in the kit.
If the spring is week it cannot hold the piston agenst the push rod and it gets pushed back by oil pressure. Thats why when you are at idel you have clutch(low oil pressure) and when you build up the revs you have no clutch.
(greater oil pressure)
Some times on cold days the oil is thicker untill the bike warms up and you can have the problem at idel as well.
When you replace the spring its best to replace the o-rings as well.