Need help...leaking Evo slave cylinder

1st the embarrassing...never did a burnout before, and just before changing my worn Metzelers for new 208s, I decided to learn. (Flame on, but I don't do wheelies and I try not to speed; just thought it would be cool. Uhh...yeah.)

Good news, I succeeded. I was a real motorcycle stud, handful of front brake and the rear wheel spinning up clouds of smoke. Bad news, I ended up slipping the clutch bad enough to smoke it. I mean literally smoke coming out of my vented cover. (You're laughing, I know you are. It's okay.) It still worked, but I replaced the clutch pack anyway.

Ever since, though, my Evoluzione slave cylinder has been leaking. I replaced the 3 O-rings twice, I even tried different sizes; I pulled the clutch rod out the other side and saw no damage, although I didn't really check it for trueness; the bearings in both the pressure plate and the piston are fine. The o-rings on the clutch rod look o-kay. I think somehow the heat did something, conducted through the clutch rod or something, but I'll be f*cked if I can figure out what.

Theres no scoring on the walls of the cylinder, and the piston is fine too. There's no evidence of a bent rod, no unusual wear marks on the rod ends or the bearing in the piston. Actuation, engagement and disengagement are all fine. Everything works, but it leaks. It drips down onto the engine case and sidestand, and even gets on the header pipe and today, after a long ride, on the tire. Not much, but any is bad.

The leak is slow enough that I haven't needed to top off the reservoir, but then again I've pulled the slave and bled the thing 3 times now, replacing the o-rings and checking things out, so who knows how long it would take...

I really don't want to buy a new slave cylinder; money's a little tight (Outer Banks family vacation coming up), but also there's nothing really wrong with mine; it's just a couple of pieces of billet. And yet, this leak...

Any ideas?

Bob,

Are you sure it is leaking from inside and not form the line? Since you have had it on and off, did you use new washers on the line? Just a thought.

They are pretty simple and if the inside walls and piston look good and you have new o-rings, don't know what else it could be?

Where in Alexandria are you? I'm right off 395 at King, but stay in Annapolis alot at my GF house.

It's definitely the cylinder. There's washers on both sides and I even lapped them. I took it apart again last night and this time I checked the clutch pushrod...wasn't perfectly straight. I straightened it (probably won't work, but sometimes I get lucky with this kind of stuff) and reinstalled it, so as soon as I get a chance to ride I guess I'll find out.

You're right, thought, the slave and piston are pretty simple parts. I think what was happening was the out of round pushrod was making the piston wobble inside the cylinder, perhaps "pumping" fluid past the seals. We'll see...

The clutch pushrod is the only thing I can think of that would cause the leak after changing the o-rings. There isn't much there to go wrong. As long as the clutch line is good and sealed, I would think that the pushrod would have to be the culprit.

It was the pushrod. Rolled across a flat surface, it was obvious it wasn't straight; there was a 1-2mm "wobble". New one's only $40, but I decided to try and straighten it in a vise with soft covers on the jaws.

A little mark w/ a sharpie on the "high" spot, clamp it in the vise, a couple of tugs on the rod, another roll across a flat surface, and guess what? Straight. Reinstalled it 2 nights ago and just put a quick 120 miles on the bike today.

...NO LEAK.

That's one of the reasons I love Ducatis...you learn something new every day!

Very cool. Glad you found/fixed the problem.
Thanks for updating everyone!

You'd be surprised what Ducati clutches can take. I had the Barnett clutch in my 104hp M966 completely and totally smoke out when someone I loaned it to dropped it then repeatedly try to get going up a hill. In 6th gear. It's fine now... does kinda squeal every now and then.

BTW, Chris: Thanks for the callback. You're aces.