So I am helping my buddy fix up his bike and the clutch is the main issue. I opened the reservoir only to find it 95% empty and very rusty. Yes, the fluid is rusty. The bike has almost 30k miles on it.
I used a hand pump vacuum bleeder and got the fluid to come out clean, but the lever will not firm up nor will the bubbles cease.
Problem that caused all of this was a non-existent lever feel (obviously) but after it sitting outside all day at work it would have some modulation.
After pulling 10+ reservoir fills through the system there is still a lot of bubbles. This is either the vacuum pump pulling air past the slave or a bad slave.
Anyone have any thoughts on what do to next?
(The slave is internal to the case, so I cannot just pull it to quickly diagnose)
you’ll always have bubbles since it will always suck air past the threads. Put a super thin wrap of thread tape on the bleed screw, tear the thread tape into a fine strip. There is liquid sealant that drys and works great, but since you’re balls deep at the moment, tape will suffice for now. Then it sounds as though the piston is leaking air… try manual bleeding instead of vacuum.
tear the master apart and see how eff’d up the seals in there are, clean, and reinstall. Al Gillen down in Holland usually has small parts like this in stock.
ok that makes sense. I did zip tie the hose to the bleeder but air around the threads hopefully explains it. I’ll manually do it a couple times and post back
Someone I talk to said it might take a few rides for it to firm up? Right now there is nothing. BUT I could move the column of fluid in the hose with the bleeder open so the master is ‘working.’ and if I pressed the lever down with the bleeder shut then cracked the bleeder fluid would come out so there is some pressure being built up by the master.
Older Ducati clutch slave cylinders are junk, might be worth replacing. Is the piston in the master actually pushing on the pin\rod sticking out of the trans?
---------- Post added at 12:10 PM ---------- Previous post was at 12:08 PM ----------
I have an older EVR clutch slave laying around I took off my 916 earlier this year, works fine, if it fits the monsters (which I’m 99% sure it does) you guys can borrow it see if that’s the problem also.
Yea, that would be sweet. The clutch slave is internal to the case so I have no way to see if the master is causing movement aside from it displacing fluid when the bleeder is open.
Ahh sorry, I thought it was external, my spare won’t work then.
You’ve probably already tried/read this but a lot of people on DMF talk about bleeding some special way involving the master bleed screw. I have a link saved at home I’ll try and find.