Ducati Monster Forum

Moto Board => Tech => Topic started by: enderwaves on July 07, 2011, 07:21:40 PM

Title: 2000 m750 revival/ clutch questions
Post by: enderwaves on July 07, 2011, 07:21:40 PM
I'm attempting to bring this bike back to life and I'm hitting a wall with some clutch problems. I've read a couple of previous posts regarding this stuff, but didn't find my specific question, answered, so here goes...
I just got the engine started, to find out that the clutch won't disengage. It seems as though the plates may be sticking together, or the pushrod has corroded (thanks search function!). Seeing as how I live out in the boonies and have to rely on the interwebs for parts, I'm curious as to what *must* be replaced when I pull this slave cylinder off. I know the master requires some new seals, but reading previous posts alluded to the ability to check the slave an pushrod without needing to order any parts.
Further info for possible diagnosis...
The bike has been dropped, breaking the clutch lever.
The master cylinder doesn't seem to be leaking, and seemed to work while bleeding the system this evening.
The lever is zip tied right now, and I'm hoping for a miracle in the morning, until then, let me hear what you think.
Title: Re: 2000 m750 revival/ clutch questions
Post by: ducpainter on July 08, 2011, 03:08:52 AM
Have you tried rocking the bike back and forth in gear with the lever pulled to see if the plates will break free?
Title: Re: 2000 m750 revival/ clutch questions
Post by: enderwaves on July 08, 2011, 04:36:37 AM
Been there, done that.

I tried it again this morning, and it doesn't seem to be freeing up any. Another note, the MC makes a squenchy noise when I pull the lever, but there is no leak, and it seemed to be pumping fluid when I bled the clutch lines.
Title: Re: 2000 m750 revival/ clutch questions
Post by: ducpainter on July 08, 2011, 07:09:34 AM
Quote from: enderwaves on July 08, 2011, 04:36:37 AM
Been there, done that.

I tried it again this morning, and it doesn't seem to be freeing up any. Another note, the MC makes a squenchy noise when I pull the lever, but there is no leak, and it seemed to be pumping fluid when I bled the clutch lines.
It may be time to pull the r/h cover to see what is actually happening at the pressure plate, if anything, when you pull the lever.
Title: Re: 2000 m750 revival/ clutch questions
Post by: enderwaves on July 08, 2011, 04:02:58 PM
Well, that just happened.

The cover is off, the plates were definitely sticking, but not in a major way. Under normal circumstances rocking the bike would've freed them up. A whole lot of nothing happens at the pressure plate when I pull the lever. I also pulled the slave cylinder, it was clean and the pushrod was moving freely. Just for kicks I pulled the lever and got a little motion out of the slave, but not very much at all.
Look like a master cylinder rebuild to you?
Title: Re: 2000 m750 revival/ clutch questions
Post by: Ddan on July 08, 2011, 05:10:37 PM
How does the lever feel?  It should be pretty stiff.  If you take the slave off and use a c-clamp to hold the piston in, the lever should be pretty solid.  If it's spongy, I'd think air, if it's firm but not solid I'd guess master.
Title: Re: 2000 m750 revival/ clutch questions
Post by: enderwaves on July 08, 2011, 05:39:58 PM
The lever feels like absolutely nothing. Almost like it never even engages the master cylinder. I'll scrounge up a clamp and report back.
Title: Re: 2000 m750 revival/ clutch questions
Post by: ducpainter on July 08, 2011, 07:48:31 PM
It could be the master...

I'd work at bleeding a bit more.

Master failures aren't very common IME.
Title: Re: 2000 m750 revival/ clutch questions
Post by: MongoReturns on July 09, 2011, 06:53:08 AM
Quote from: ducpainter on July 08, 2011, 07:48:31 PM
It could be the master...

I'd work at bleeding a bit more.

Master failures aren't very common IME.

I'd be really surprised if it's the master.  For thorough bleeding (run out of fluid in master) I've taken the slave off & put it up as high as possible.
Title: Re: 2000 m750 revival/ clutch questions
Post by: Howie on July 09, 2011, 01:54:13 PM
Quote from: MongoReturns on July 09, 2011, 06:53:08 AM
I'd be really surprised if it's the master.  For thorough bleeding (run out of fluid in master) I've taken the slave off & put it up as high as possible.

There can still be air trapped in the master.  Either position the bike so the master is horizontal and bleed or remove the slave and slowly push the piston back.  Then tie the lever to the bar in the disengaged position.

Do what Dan said too.
Title: Re: 2000 m750 revival/ clutch questions
Post by: enderwaves on July 12, 2011, 12:27:41 PM
Not the master.

Ended up sitting down saturday to try bleeding the clutch some more. At this point, I thought I was dealing with a tiny amount of air, so I was working at the slave cylinder bleeder valve. Just when I have all of the bubbles out of the line, an huge one would pop up. Well, turns out air was leaking past the diaphragm in the reservoir. I cleaned up the reservoir, flushed everything, and it's holding pressure now. I put a new cap and diaphragm on order as well. So now the clutch lever is super stiff, I'll know tonight if it's going to work or not.