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Clutch issues

1K views 6 replies 3 participants last post by  fester 
#1 ·
Guys I'll reprint a question I posted on the Paso forum as I'm after additional feedback from you guys. I originally posted on the Paso forum as my bike is an 89 900SS and as such the clutch is more in common with the 906 Paso than the 91 on SS's. Having said that the reasons for my problem should be generic and I'm sure someone has experienced something similar and there seem to be far more opinions expressed here that say Paso.org (good or bad).

For those that don't know the main difference from my clutch to later models is the slave is in the cover on the right side so actuates pretty much in mirror image to you guys. So all I have is basket, hub, plates and a pressed steel pressure plate with the springs on the underside or engine side and the slave actuates on the outer side of this steel plate.

So here's my problem:-

I had noticed before winter and the last couple of early winter rides that my clutch started playing up a bit.

A couple of times it remained disengaged after releasing the lever so not sure if the master was sticking or the slave. Second pull and was normally right and onyl happened a handful of times. I suspected the slave on that occasion (but haven't touched) as the master is a reasonably new and buy all accounts good condition remote res version with the large pivot pin like early SBK's and I think later injected SS's and ST's.

Last couple of times I rode before pulling front end apart I noticed it was a bit notchier when engaging first but didn't really think anything of it. When front was apart I pulled the clutch cover removed all the plates and blew out all the dust. Looked at plates but didn't touch and put back in in same order ( apart from maybe turning back to front the odd friction and steel plate but not the outside thick one).

Now bike is back on road the clutch is worse. No leaks but harder to get into first and creeps a little. Sometimes stalls at lights when you miss neutral from second and get first at low revs. Used to find neutral fine but hard now overshooting from both first and second. Also hard to change down on the move sometimes. Up shifts still fine and no jumping out of gear or anythign else strange.

Initially thought it time to look at new plates but then realised that worn plates would create slip which is not happening.

So my suspects would appear to be either the master or the slave but neither appear to leak. Also given the slave will surely be much older than the master I thinking that. Would it likely be crud in there somewhere stopping the slave from extending to correct depth. This is my next path of investigation but any ideas to help speed the diagnosis.

Also on the subject given the differences between new and old clutches what the best option as far as getting updated/new clutch plates and say springs for the older clutches.
 
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#2 ·
Sounds to me like the basket is worn and has the notches in the fingers from wear.

You'll have to pull it apart to verify. I had a Paso many years back, and only had problems with the slave cyl. leaking slightly. Cleaning the slave up and a new o'ring fixed that. But notchiness sounds like the plates are being hung in the basket.

Unsure about getting the correct basket for it...
 
#3 ·
Thanks Stick I did have it apart the day. Thought while I had it off the road fitting the SBK front end I might as well clean it out but it was already playing up before that. Whilst I didn't look at the basket or anything else in great detail as I'd forgotten how bad it had become I did look at most bits and didn't really see any great wear. From memory the basket and hub both looked reasonable, of course now close inspection is warranted.

Also noticed today that it was a bit noisier and the sound had changed, not sure how to describe as it only happened a couple of times but almost a bit of a squeal so maybe the slave piston is playing up.

Need to pull it this weekend and have a close look.

Any way to diagnose the master if it's not leaking to definately rule out that end.
 
#4 ·
If I'm not mistaken, two of the steel discs are beveled, the other steel discs are flat. They are not significantly beveled, you'll have to look at them on flat surface, like a pane of glass.

As I recall, if the high point of the ring is the inside diameter, it should be pointing towards the engine when assembled in the clutch pack. If one of the rings is reversed it may be dragging on a friction disc, which is causing it to be difficult to shift into neutral.

Make sure the slave piston is cleaned and well lubricated, you may have to pull the bearing seal off and disassemble it. They are far and few between.

Hope that helps.
 
#5 ·
Thanks J?ack so far no joy the bearing/piston assembly looks OK as I would expect after only having new fluid less than 12 months ago and bearing is fine. I have some issues about the overall height of that piston assembly but that should be addressed on the paso forum.

Plates didn't look too bad I don't think they were back to front but I only looked quickly. Order was not the same as was posted elsewhere so I might follow that on reinstal.

Next questions for the masses:

Is there a simple way to test the function of the master cylinder. It's not leaking but could it be bypassing the seals internally without leaking. Can they be disassembled to clean and inspect.

Can anyone with a late model clutch spring lying around measure one for me. You know ID, OD and free height. Whilst I have mine apart I'm looking to replace everything that's cost effective (and available) and I haven't found a listing for the older springs but maybe they are the same as the later ones.

And in a joking but semi serious tone anyone know an easy way to drill out my input shaft without completely dismantling the engine. Putting the later style clutch assembly in place would certainyl make it easier to get good parts and that's all that's stopping it from being feasible.

Why would Ducati have put a blanking plate where the left side clutch slave should be on a 1989 model when the left side slave was only introduced from 91, was it just to tease me???
 
#6 ·
Just a couple of comments, the clutch slave can be rebuilt, but it's not easy. You may need three or four hands, there maybe a Ducati "special tool" needed to hold the piston in place. To test it, to see if it leaks or has a slow leak, you could blank off the hose end and apply pressure to the lever.

I might have the spring dimensions in the manual at home. I'll try to remember to check them tonight. They're probably the same as the SS vintage springs, the clutch pack is.

I have no idea why Ducati put the slave on the cover, probably one those things the engineers all laugh about when no one else is around. I'm not sure you could put a slave on the opposite side and use a push rod. Wouldn't the clutch pack move in the opposite direction to disengage?
 
#7 ·
Actually Jack I've got rebuilding the slave sussed it's not too bad. From what I understand the earliest versions had an arrangement where the actuating pin had the ball race built into it and you installed the loose balls into the piston then the pin/race, a circlip to hold it in place then a seal.

The later (old style) version had a modern roller ball bearing seated in the piston and the pin sits in the bearing. The trick is getting the old bearing out. Can be done by welding a nut to the bearing inner and using as a bearing puller or if the bearing sits proud of the piston weld somethign to the outer shell. This will shrink the shell and provide a surface to grip and pull. Or if like my spare cover the bearing is totally stuffed you can pull the inner and balls out and weld something across the inside of the shell to do the same as just mentioned.

I also now believe the piston assembly from the current range of bikes can be used as a replacement assembly for the older ones or the current style oring can also be used individually as it's a better style.

What I now want to find out is if the late model springs are close to the same as I'd like to upgrade those while I've got it apart.

My understandign at present also is the late model clutch pack is not the same, limiting my clutch pack options to the very few suppliers who make them for the old bikes.

Must try that blocking the line to test pressure. I have one of those little dinky brake hose clamps that you use to stop all the fluid draining out so whilst I still have a rubber line I'll clamp it and test that. Will be replacing with a braided line as part of the upgrade as the original is looking a bit ordinary.
 
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