12 replies to this topic

[tombo46]

I had a pretty strange clutch problem and tried everything suggested in my other thread http://www.trialscentral.com/forums/index....showtopic=23672.

after holding the lever in for some time both while running and not running, and while the clutch is under load (like described in the other thread) I found that no fluid was going back into the master cylinder.

So I decided to take the clutch casing off and have a good look at it all. I took the slave cylinder "top hat" off and looked at the seals, they both looked good, no tears, wear or anything like that.

However one problem I found after taking the clutch basket out was that all the fingers werent level. there was a couple that were about 1 - 2mm lower than the rest. could this be the cause of my problem?

Ive decided to fit a new clutch pack anyway while everything is out, im hoping somehow this will solve the problem. anyone else got any suggestions?

Thanks for all your help up to now =]

Tom

[husky]

I wouldn't just fit a new clutch pack,these clutches slip not drag when worn.The fingers aren't the problem either,change the seals in the top hat part,they don't always look worn and they are known for giving the problem you have.You won't see fluid returning to the master cylinder,it's leaking into the gear oil

[tombo46]

husky, on Feb 23 2009, 05:30 PM, said:

I wouldn't just fit a new clutch pack,these clutches slip not drag when worn.The fingers aren't the problem either,change the seals in the top hat part,they don't always look worn and they are known for giving the problem you have.You won't see fluid returning to the master cylinder,it's leaking into the gear oil

Ive ridden it for about 15 hours with this problem and ive not lost any fluid out of the master cylinder. could it still be the slave cylinder seals?

Tom

[exvet]

Sounds like the master cylinder compression seal is allowing the fluid to leak around the piston back into the reservoir.
Provided there is no scoring to the bore, should be an easy fix with a cylinder rebuild kit.

Tim

[Spenser]

I didn't read your previous posts, but we had a batch of clutch master cylinders on mid-year 2007 bikes that weren't properly cleaned/deburred, this caused dragging and was repaired by replacing the master cylinders under warrantee. I disassembled the masters and found all sorts of filings etc. that scored the seals.

Best of luck
Spencer

[tombo46]

exvet, on Feb 23 2009, 06:53 PM, said:

Sounds like the master cylinder compression seal is allowing the fluid to leak around the piston back into the reservoir.
Provided there is no scoring to the bore, should be an easy fix with a cylinder rebuild kit.

Tim

If this was the problem, wouldnt the clutch start to pull after a while with the lever held in? I can hold the lever in for as long as I want but it only starts to pull if the clutch is having to work hard (like pushing it against a rock for balance), during normal riding theres no problem at all.

Tom

[exvet]

I missed the previous thread where you discussed the water pump seal replacement. could be contaminated clutch plates. I had an 02"
edition model that the friction material lost its bond with the clutch disc after coming into contact with the coolant/trany fluid mix.
this caused the clutch action to become more inconsistent over time to the point where the clutch would no longer disengage.

I would inspect the friction discs closely for this.

Tim

[tombo46]

Ive put a new clutch pack in. new slave cylinder seals and new master cylinder seals and its still got the same problem! any other suggestions?

All the best

Tom

[Baldilocks]

tombo46, on Feb 25 2009, 06:05 PM, said:

Ive put a new clutch pack in. new slave cylinder seals and new master cylinder seals and its still got the same problem! any other suggestions?

All the best

Tom

from your photo of the bike you have red hoses fitted. check that the hose isnt expanding somewhere under pressure. It will be harder to spot the problem with the red hose and maybe thats why you havent noticed it ?

Had this on a montesa with a Venhill replacement brake hose a few years ago

[tombo46]

Baldilocks, on Feb 25 2009, 10:31 PM, said:

from your photo of the bike you have red hoses fitted. check that the hose isnt expanding somewhere under pressure. It will be harder to spot the problem with the red hose and maybe thats why you havent noticed it ?

Had this on a montesa with a Venhill replacement brake hose a few years ago

Ill swap it back for the original hose and see how it go's, the thing that baffles me is why does it only do it when im pushing the bike into a rock? why doesnt it cause any other problems!?

Tom

[HAM2]

....well?.....

[elmetal]

You generate heat when slipping the clutch (balancing against a rock, pushing) and some of this heat causes the clutch fluid to expand. This back pressure might be enough to swell the new lines you put in and allow some of the presure at the top hat to reduce. Unless the new seals have been nicked already I'd say the lines are worth a look, you've replaced just about everything else.

[samwilk200]

Have you sorted this yet?! Interested as I know of someone with a similar problem!