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!
At 8000 mi. you are well within the neighborhood of wearing out a clutch. If you were to take the clutch pack apart and measure each disc with a vernier caliper and if you knew what the original thickness of each plate was, you would probably find that each plate was something like .020"-025" thinner than they were new. Add up all those plates times .020" and you have reduced the "stack height" to a point where the spring pressure is insufficient to fully lock up the stack, resulting in slippage.
I have taken a clutch pack apart and done this and compared with new plates and thats what I found - new plates maybe .135" and the worn plates something like .110". That's one reason I keep old plates so when I start to get slippage I can replace worn plates with old, but almost full thickness plates and get no slippage - it's a short term fix.
Buy a new clutch pack. Takes about 30 min. to change out. The Barnett red plates are cheap (Ca-CycleWorks), but don't last as long as the OEM plates. And FWIW, the 14 tooth does help a little on getting off with less intentional slippage on your part, if you know what I'm getting at.
I'm very good to my clutches, always in neutral at stop lights and easy on take off etc., and that's about all I get out of em.
Of course YRMV. ;D
LA
Idk about that, LA. I mean, I've been flogging the S4R for quite some time-it's got 27k on it and it's still on the original clutch. What are you doing to yours?
I've been having the same problem (slippage) with my 999.. its like when i shift into first with the clutch held in, the rear wheel starts to move. Also getting into neutral has been a pregnant dog lately... time for a plate kit??
To: Mr Bread
You are having the opposite problem of slipping, worn plates. You aren't getting full release which can be a leaking slave, air in the clutch hydraulics, the clutch stack height is slightly too high or the plates are sticking.
Mac,
So i do not have worn plates which are slipping.. I have a leaking slave, air in the hoses, or stack hight is too high or stickey plates.
I've had the bike for 3 months now, put around 5k on it and have had no problems until recently.
What would make the plates stick? and is there any trick to bleeding a clutch?
Thanks
Your fluid is probably getting old. I bleed them every 3,000 miles. It really depends on how much you abuse your clutch. my fluid goes pitch black in a matter of days, where someone elses goes black over the course of a 2 months. I ride the clutch alot because of traffic and over all urban abuse.
It takes maybe 30 min to dissemble the clutch and inspect it. If it is slipping as in engine build revs that don't get translated into MPH, it's probably a combination of lack of friction material left on the plates and stack height. I can't see it being hydraulics. Seems like hydraulics would affect disengagement rather preventing lockup. ? [roll]
??LA
engine keeps disconnecting to the wheel = slipping plate (plate cant transfer 100% power)
Engine wont disconnect from the wheel = air in clutch, STICKY plates that prevent full disconnect, (plates will not disconnect 100% power from engine)
I have the later problem. caused by learning how to do burnouts. [laugh] still good though.
I guess the clutch operation concept is kind of hard for some folks to grasp and harder for others to grasp completely. No sweat. I get to explain it all the time in my line of work.
Worn plates, which can cause slipping are the main cause of slipping. Slipping being where the engine revs up but the bike is either not moving enough with the engine or isn't moving at all with the engine.
Worn plates = a clutch that is near to disengagement. Symptoms show up as slipping when shifting gears or when accelerating, i.e. twist the throttle and the engine revs up but the bike barely accelerates. Since a slipping clutch is almost disengaged worn plates will never cause difficulty in finding neutral or shifting into gear. Worn plates will never prevent an engine from full disconnect but, rather, will never allow full connect. Slipping can also be caused by worn, weak springs in the pressure plate. Once in a great while, very rarely, is there a problem in the hydraulics where something is not allowing the complete release (engagement) of the clutch.
On the other side of the coin anything that would cause the friction plates to stick to the metal plates would cause problems selecting gears, finding neutral and possibly even stalling with the clutch lever pulled all the way in (clutch disengaged) but the bike still in gear, i.e. shifting into 1st at a stop and having the engine stall immediately. Clutches can stick due to rust (for dry clutches), dirt, expansion of the friction plate material or warping of either the friction plates or the metal plates. It's also possible for the clutch to not fully disengage because the entire clutch housing is coming loose from the input shaft. In that case the clutch housing is moving away from the clutch release rod so the rod can't push the pressure plate far enough out to allow the plates to separate.
The symptoms and causes of the two conditions are separate. You could, I suppose have worn plates and a leaking slave at the same time. That would be kind of messed up but still possible so that combination would make diagnosis a little harder. Woe be it to the tech who would have to explain that to the customer.
Mac,
Thanks for laying it out like that. Seems like i have some sticky friction plates, or perhaps the the housing is moving from the release rod.
When i pull the clutch in, its like nothing is happening, the revs go down a LITTLE, like 500rpm and you can hear the clutch doing is 'dry clutch sound' for a fraction of a second, then its like i dont even have the clutch pulled in anymore. I have adjusted the lever to allow the maximum travel from lever to bar to see if it would help and it seemed to for a little while then it didnt even matter. On my way home last night I had to shift w/o the clutch, except for 1st from a stop which was like dumping the clutch, (stalled a few times).
So for sticky plates.. do i just take them out and clean them off? Or is there a super secret ducati trick to it?
Thanks for the help guys, and sorry for totally jacking this thread.
Back on topic, did LA ever get his clutch issue sorted?
Quote from: Mr Bread on August 18, 2008, 06:16:34 AM
Mac,
Thanks for laying it out like that. Seems like i have some sticky friction plates, or perhaps the the housing is moving from the release rod.
When i pull the clutch in, its like nothing is happening, the revs go down a LITTLE, like 500rpm and you can hear the clutch doing is 'dry clutch sound' for a fraction of a second, then its like i dont even have the clutch pulled in anymore. I have adjusted the lever to allow the maximum travel from lever to bar to see if it would help and it seemed to for a little while then it didnt even matter. On my way home last night I had to shift w/o the clutch, except for 1st from a stop which was like dumping the clutch, (stalled a few times).
So for sticky plates.. do i just take them out and clean them off? Or is there a super secret ducati trick to it?
Thanks for the help guys, and sorry for totally jacking this thread.
In your case I would verify that the hydraulics are in good working order first of all. Make sure the line is bled properly and then test it. If it shifts OK at first and then gets worse it's likely that you have a bad slave. You could also remove the slave and inspect it for leaks. BTW, you should remove the slave anyway before taking apart the pressure plate & discs.
Update on the S4: I took it for a test ride last night, and it seemed fine around town, no slipping. Took it across the bay bridge to work in SF this morning, and it's still fine (it's a nice cool day today). Seems that the heat last week contributed to the situation.
Not gonna test my luck though, gonna take it into the shop later on this week. Eventually I'd like to learn how to work on the clutch myself but unfortunately I'm not quite there yet... for now I'll let the professionals take care of it.
Quote from: mxwinky on August 16, 2008, 03:56:40 PM
Yeah, the clunk going into 1st gear is totally normal, but having a hard time getting into 1st is not normal.
Interesting... thanks for the info. Just to clarify, I should have said that I have a hard time getting into first without a little clunking. I always try to get the exact ratio of throttle to clutch that results in no clunk, and sometimes I think I'm gonna stall so then I give it a little too much throttle before the clutch is fully engaged and then comes the clunk. Does that sound normal?
Quote from: Bigbore4 on August 18, 2008, 06:39:11 AM
Back on topic, did LA ever get his clutch issue sorted?
What issue? You mean that I wear clutches so fast. I dunno. They're easy to install and I have em either all the way in or all the way out and always go to neutral at stops. I ride the bike pretty hard, but so does everybody. Don't know.
It's really only the Barnett's that I wear out, it that's what you mean.
LA
Turns out all i had to do was bleed the clutch. Apparently the fluid boiled.
Thank you all for the help!
There you go! [thumbsup]