I recently had the clutch fluid on my 2001 S4 drained and replaced at Munroe in SF, and yesterday I was riding to my place in the east bay... It was really hot, it was rush hour and I was lane sharing in 1st and 2nd gear for a good while on route 24 before the tunnel, and my clutch started slipping for the first time ever.  The bike has 8000 miles on it and I'm pretty sure it has the original clutch pack.

I haven't tried riding again without the bike being warmed up to see if the clutch still slips while cool, I know I need to do that.

Anyway, I'm wondering if the problem is most likely worn plates, or if maybe the work that they did at the shop caused the clutch to slip. Is it possible that they accidentally blocked the bleed hole in the clutch master cylinder while working on it?

Regardless, I'm gonna take it into the shop and let them take a look at it (probably take it to Ace since the bike is currently in the east bay).  Just wondering if you guys have some insight on what the problem could be... 

Thanks in advance for any helpful info!

Air in the system would cause you not to be able to fully disengage the clutch.  The engine would still be trying to move the bike some while you had the clutch lever pulled.

The only thing responsible for keeping the clutch from slipping is the friction surfaces and the clutch springs.


edit:  Well, I guess it's possible that the slave cylinder is getting stuck, or something like that, but I've never heard of anything like that happening.

You're slutch should last quite a bit longer than that. You should have a problem that isn't worn plates.


I haven't heard anything good about Munroe's in SF, for the record.

Good to know.... thanks guys.

Well, I guess I'll drop it off at Ace Motorsports next week and see what they find.

clutch wear depends on rider and conditions.  there isn't a "rule" for how long a clutch should last.

my guess would be the shop didn't bleed the clutch properly.  Go back and have them check.  even paid ducati mechanics make mistakes.

I changed a clutch on one of my bikes recently and the plates were visibly worn.  even with that I still had to get on the clutch pretty damn hard to make it slip.

Alot of work goes into destroy clutch plates. Theres quite a bit of reasons why it would slip before you can reach worn plates at 8k miles. I am at 8500 right now and i have slightly the same issue. In fact. i need to post up and wonder what the hell it is.

Also make sure the reservoir is not too full.

Thanks for the replies!  Just the sort of info I was looking for.

One thing I forgot to mention is that I'm a total noob, been riding for about a year, the S4 is my first Ducati. So when I was first getting used to the S4, I totally abused the clutch from inexperience.  I know it was a little crazy to go to a 916 so soon, and I still have trouble getting into 1st gear sometimes.  Would it make it easier to get into 1st if I change to a 14 tooth in front?

Also, how bad is it to ride with a slipping clutch?  What are the chances of it going out completely?

I would think if the shop bled the system and made a mistake of some sort, it wouldn't lead to slipping but the opposite. You wouldn't be able to disengage the clutch.

Maybe the newly bled, and now properly working, system allows for additional clutch disengagement that wasn't available before, which is just enough to allow a marginal clutch to start slipping?

The clutch on my 750 started slipping @ 9k miles. It also got worse when the engine was hot. I replaced the clutch pack and all was well.

Quote from: ride_sf on August 15, 2008, 05:02:19 AM
Would it make it easier to get into 1st if I change to a 14 tooth in front?

Also, how bad is it to ride with a slipping clutch?  What are the chances of it going out completely?

a little slipping is required in first, due to the extra-tall first gear on duc's, but you should try and limit it to that.

i never went to the 14 tooth front, but an extremely large number of people swear by it. certainly something to look into when you change your chain and sprockets.

Quote from: KEH on August 15, 2008, 05:25:26 AM
I would think if the shop bled the system and made a mistake of some sort, it wouldn't lead to slipping but the opposite. You wouldn't be able to disengage the clutch.

That's correct.  IF there's air in the lines, pulling the lever won't have the desired effect of fully disengaging the clutch.

I did have an issue where I over adjusted the plunger push rod on my clutch master after putting on new levers.  This had the result of partially blocking the return port in the master and meant the clutch would not engage properly since the fluid would not clear out of the slave, but into the reservoir.

But -that being said - your shop should not have touched that adjustment if they just bled the line as a maintenance item.

One simple thing to check - are all your clutch spring retainer bolts 100% in?  I know a couple of mine backed out at one point...

One thing you could try in the meantime is switching the order of the plates + flipping them, so the surfaces making contact aren't already "mated" to each other. I too ride an '01 S4, and when I installed my open pressure plate I did this, which seemed to help the clutch grab more effectively since the surfaces making contact are new to each other.

obviously your plates are still worn + you'll want to replace them. This is just a "band-aid" fix mind you, but flipping + repositioning the friction plates would probably buy you some time until you can get a new clutch pack.   

We had this issue on a 95 M900.

After numerous bleedings (vacuum from the bottom), fluid change, you name it we finally found the trouble.

We had observed that if you cracked the bleed screw with the system at rest hot, there was pressure and it would spurt out a bit of fluid.  The clutch would then function normally for a period, until it got hot again.

The bike was 11 or 12 years old with less than 3K miles.  I finally found that the port (there are 2 ports, coffin style master) closest to the outlet of the master was blocked with some sort of debris or sludge. 

Carefully cleared with a toothpick, end of problem!  It was not allowing the fluid to completely bleed off, so the slave could not fully release when the fluid heated up and expanded.

Hope that helps!

Quote from: ride_sf on August 15, 2008, 05:02:19 AM
I still have trouble getting into 1st gear sometimes.  Would it make it easier to get into 1st if I change to a 14 tooth in front?

A clutch that doesn't completely disengage makes it tough to find neutral and it might make it a bit clunky going into first but a lot of our bikes clunk into 1st especially with a hot engine.

A 14 tooth front sprocket has no effect whatsoever on 1st gear engagement. It just makes taking off in 1st a little easier plus it gives you an extra punch through all the gears that results in a decrease of top end speed.

Yeah, the clunk going into 1st gear is totally normal, but having a hard time getting into 1st is not normal.  Usually when that occurs it's caused by the clutch dragging a bit and not releasing completely with the lever pulled in.  I think you've definitely got a problem related to the fluid change and subsequent bleed of your system.  The stock clutch slaves aren't that great either so if you'd like to make your lever pull a good bit easier and get it done again I'd recommend one of the aftermarket clutch slaves from either Evoluzione, Yoyodyne, or STM.  Much better than stock, you'll immediately notice that your fluid stays clear instead of turning black from seal degradation in the stocker.  While your plates may be worn after your newbie abuse, i'm betting that a proper re-bleed cures the problem.  Good luck!