Clutch Bleeding Help.

[craigrevo]

Is there a special procedure to bleeding the Gasgas clutch? So far I've tried standard on off bleeding, reverse bleeding with a syringe, suction bleeding with a syringe, and vacuum bleeding with a mates kit.

I'm using atf mineral oil as I use in my KTMs.

I've now ordered a new bleed nipple and some LHM fluid to try and rule everything out.

The clutch has feel but no engagement.

[crazybond700]

Pro engine? Or older?

 

There are 2 systems for the pro's (more actually), but basically mineral and dot. It does take a while somethimes to get the air out, but it does not work very different from air bleeding a brake system. I use a vacuum system, which will suck the fluid trough the system and take out the air. Does take a while to bleed when the system has been completely dry. I loosen the adjusting nuts on the lever to prevent problems with flow there. Make sure the basket is full with fluid and bleed. The old, open nipple, pump, close system will work fine aswell. Just use a piece of (transparant) tube. Somethimes in the beginning nothing happens, pull the lever a bit etc and it will start.

 

Also make sure you mess a bitt with the lines and turn the bars. This will help airbubbles to go to the top. Pull the lever a bit, soft and some harder (mind the overflow/your eyes/the mess etc ), once you done it more often you will get the hang of it.

 

What did you do? this can also help the story. (why is it in need of bleeding, etc)

Edited April 28, 2015 by crazybond700

[craigrevo]

It's a 2005 300 raga. I removed the top hat from the slave so I could paint the inside of the case.

I've done loads of work on bikes in the past including bleeding clutches but this one is having none of it. So if it's a normal bleeding system it must have a problem. I'm leaning towards the bleed nipple as it is a little loose.

Edited April 28, 2015 by craigrevo

[crazybond700]

Than there is only small amount of air in. But sometimes it can be a bit of a struggle. If you open the nipple and than press the lever, fluid comes out?

[eddie1]

I've always had good success pushing fluid back from the bleed nipple on the case back up to the master cylinder.

If the case is off make sure that the slave cylinder is full of fluid and the piston pushed right in. Not sure if this is necessary but it must help.

First make sure that the adjuster screw on the master cylinder is wound out so that the piston is not engaged.

Open the bleed nipple on the case enough and push fluid  through with a syringe. Watch the fluid as it comes out in the master cylinder. You should see bubbles come out and eventually clear. You may need to stop and empty the reservoir a couple of times.

Lock the nipple and try it. If it is still not bled, with the nipple still closed keep tapping the lever so that the piston makes tiny movements. Sometimes you will see tiny air bubbles come out as you watch the fluid in the cylinder..

If it is still not right repeat the process.

 

I've never had any success bleeding any hydraulics on a gas gas by pumping the lever and opening the bleed nipple.

The pushing the fluid back with a syringe method has worked for me on the clutch and front brake. The rear brake has been another matter although I have eventually found  a method that works for me on that as well.

Good luck

[baldilocks]

This is how i did mine recently when i changed the hose. With the hose removed fill the hole in the case so you know the top hat has fluid. Fit the hose with new washers and fill the master cylinder. Turn the bars full right hand lock so the master cylinder is the highest point. Then pump the lever, takes about 10 minutes and all the air will be out. Make sure the lever adjuster is backed off as there must be free play in the system. If this doesn't work then you have an air leak

[steve_earle]

It can take a while to bleed the air from the clutch system, Keep at it, Some people give up too early assuming there's a problem.

 

I take it you didn't paint the shaft.

 

On another note, nothing to do with the bleeding issue, I'd be cautious of painting the inside of engine covers, Unless using proper etch primers and chemicaly stable activated 2 pack paints, Atf especially could react with the paint leaving a nice mess in the gearbox.

[crazybond700]

I've always had good success pushing fluid back from the bleed nipple on the case back up to the master cylinder.

If the case is off make sure that the slave cylinder is full of fluid and the piston pushed right in. Not sure if this is necessary but it must help.

First make sure that the adjuster screw on the master cylinder is wound out so that the piston is not engaged.

Open the bleed nipple on the case enough and push fluid  through with a syringe. Watch the fluid as it comes out in the master cylinder. You should see bubbles come out and eventually clear. You may need to stop and empty the reservoir a couple of times.

Lock the nipple and try it. If it is still not bled, with the nipple still closed keep tapping the lever so that the piston makes tiny movements. Sometimes you will see tiny air bubbles come out as you watch the fluid in the cylinder..

If it is still not right repeat the process.

 

I've never had any success bleeding any hydraulics on a gas gas by pumping the lever and opening the bleed nipple.

The pushing the fluid back with a syringe method has worked for me on the clutch and front brake. The rear brake has been another matter although I have eventually found  a method that works for me on that as well.

Good luck

Trick with brakes which often helps ones you have got some pressure, tiewrap or glue clamp the brakelever/pedal. Next morning will be as hard as a ****

[Yerbuddy]

I have a 2004 Gas Gas TXT280 Pro.  I am having problems with the clutch not disengaging fully.  I have tried "tuning" the friction discs (cleaning excess resin from between the patches) and sanding the metal plates.  I even installed a brand new Gas Gas factory clutch pack and saw no difference.  The clutch pack measures within specs and the basket shows no galling or damage.  I also tried pushing DOT 4 backwards through the slave cylinder with a syringe, but was unable to get fluid out the other end.  What am I missing here?

[lineaway]

 I may be wrong here, but I thought all pro's took mineral oil.

[richt]

A 2004 pro clutch should use brake fluid. They changed in 05 / 06 and started putting a dark green top on the master cylinder to indicate it's changed to Mineral oil. 

[lineaway]

 That's right, but my 04 Raga 300 was mineral oil. But back then they were basically the next years model.

[lineaway]

18 hours ago, Yerbuddy said:

I have a 2004 Gas Gas TXT280 Pro.  I am having problems with the clutch not disengaging fully.  I have tried "tuning" the friction discs (cleaning excess resin from between the patches) and sanding the metal plates.  I even installed a brand new Gas Gas factory clutch pack and saw no difference.  The clutch pack measures within specs and the basket shows no galling or damage.  I also tried pushing DOT 4 backwards through the slave cylinder with a syringe, but was unable to get fluid out the other end.  What am I missing here?

Did you change out the o rings in the slave/clutch cover?

[eddie1]

21 hours ago, Yerbuddy said:

I have a 2004 Gas Gas TXT280 Pro.   I also tried pushing DOT 4 backwards through the slave cylinder with a syringe, but was unable to get fluid out the other end.  What am I missing here?

If you can't get the fluid to come out in the reservoir my guess is that you need to fully screw out the adjuster screw that goes against the piston as this may be holding the piston in slightly.

You should then be able to push fluid up from the bleed nipple up to the reservoir with a syringe. Obviously the reservoir cap needs to be off. Watch the fluid coming up, initially there will be some air bubbles but it should then go clear. 

Lock the nipple up, screw the adjuster back in until it just touches the piston. Then slowly operate the lever alternating between short and full strokes. Hold the lever in and tap the hose. Keep looking at the fluid in the reservoir as you may see small air bubbles come up. Once you are sure they have stopped. Refit cap and try it out. It should be OK.

[arbutus]

Two weeks ago I had to replace the 2 O-rings in my 2009's slave cylinder after 13 year's of service. Up to that point all I ever did for servicing was fluid replacement by adding mineral oil to the master cylinder reservoir and vacuum bleeding through the bleed screw. Because the system was entirely dry after the O-ring replacement, I filled the floating slave cylinder/piston/top hat until it had a meniscus then slid it over the stationary piston which is part of the clutch cover. The cover was off the bike and held so that the slave cylinder/piston assembly was vertical, thereby not allowing air to enter the system from this end. There is enough oil capacity in the  floating piston to fill the fluid passage in the clutch case completely to overflowing. The case can then be reassembled on the clutch side of the engine. Top up the fluid in the banjo bolt hole before reassembling the hose and banjo bolt. One interesting thing I found was that the slave cylinder's internal spring and guide were assembled by the factory in reverse order to that shown in my 2009 parts book. I put them back together the way they came out, figuring they worked fine this way, after all this time. On the end of the spring that went into the clutch case, I opened up the first coil, so that it would stay inside the case's fluid passage without falling out when being held upside down. At the other end of this spring, I slightly squashed the first coil, so that it would retain the plastic spring guide for the same reason.

With the clutch cover back on the engine, and the hose reattached with the banjo bolt, I now refilled the master cylinder's reservoir with Shimano mineral oil. I had the lever free play adjustment screw backed out all the way so that the compensating hole between the reservoir and master cylinder was not blocked by the piston. I expected gravity to take over and fill the hose down to the banjo bolt, saving me some work. No way. To get it started, I pumped and held the lever with the bleed screw removed, then I covered the hole in the banjo bolt with a finger, only then did I release the lever. After six or so cycles of this pumping action there was enough fluid in the hose to start a syphoning action, and gravity took over. This was a fast flow, and I had to be quick to refill the reservoir before it sucked air. With fluid coming out of the banjo bolt's hole, I squeezed and held the clutch lever, momentarily sealing the system, allowing me to install the bleeder screw. One more pump with the bleeder screw cracked open then closing it for good. Another pump with the banjo bolt just cracked enough to weep, then tightening it, and I was done. The clutch has worked fine on a couple of rides since, and I did not have to get my vacuum bleeder out for this job.

I hope this procedure may help someone else. The photo is from the 7 hour test ride up Mt. Irwin (4300ft.) , down and up the saddle to the top of Mt. Hal (4880ft.), then dropping back to basically sea level. This small lake is on Mt. Hal. Cheers.