It's back - clutch slipping again :(

[marchesini]

Well after a few days of a slipping-free clutch, it has returned. Not nearly as bad as before but it has started playing up again.

So after watching how Rob did it last weekend, I did the same. Clutch plates out, scotchbrite, brake cleaner and reassemble. Worked for about a day and then started slipping / grinding again. It doesn't slip under power, only when from a standstill / traffic lights.

Any idaes on what to try next? I have another two ducatis which are just sat in the garage. Should I swap over the plates and see if that helps or is it better to just buy some new plates and be done with it? The plates however look ok, no tangs or wearing of the teeth so new plates might not do the trick.

Slightly reluctant to take it to a dealer as the labour cost would be as much as the plates - would like to try to fix myself first (credit crunch and all that). It also seems like one of those things that will be 'fixed' for the first few miles and then return so would be hard to know whether they has actually fixed it for good until a long term test - if that makes any sense.

So, swap plates from my 853 or 996 or just buy some new plates. Or is it likely to be something more sinister?

Cheers

[Capo]

I think you need to look at the slipper mechanism, that will involve removal of the hub.

[Kato]

Simon, I'd say that the stack height is wrong.... rode mine around for ages with the exact symptoms as you have just because I was to lazy to sort it out, If you lay all your plates down as they go in the clutch the stack should be 38mm high +/- 2mm.

Hope that helps?

[marchesini]

Simon, I'd say that the stack height is wrong.... rode mine around for ages with the exact symptoms as you have just because I was to lazy to sort it out, If you lay all your plates down as they go in the clutch the stack should be 38mm high +/- 2mm.

Hope that helps?

And what can I do about it? DO I need to buy anything or simply adjustments?

[slob]

Either replace the plates or add an extra driven (steel plate)
Full info here http://www.mad-ducati.com/Technical/BucciSlipperClutch/BucciSlipper.html
Also check the convex plates are in the right places (page 4)

[marchesini]

Either replace the plates or add an extra driven (steel plate)
Full info here http://www.mad-ducati.com/Technical/BucciSlipperClutch/BucciSlipper.html

The plates are not cheap (about £200?) and don't seem worn so should I try adding the plate. I don't have any lying around so will this do:

http://cgi.ebay.co.uk/Ducati-Clutch-steel-plates-748-916-996-998-not-friction_W0QQitemZ400037024097QQcmdZViewItemQQptZU K_Motorcycle_Parts?hash=item5d24109161&_trksid=p3286.c0.m14&_trkparms=65%3A12%7C66%3A2%7C39%3A1%7C72%3A1689%7C 240%3A1318%7C301%3A0%7C293%3A1%7C294%3A50

Seems worth a punt?


Also check the convex plates are in the right places (page 4)

Don't recall having any convex plates Rob - do you? They all looked the same to me? Maybe that's why it's not working?

[Kato]

Simon you really need to measure so you will need a vernier if you want to be accurate

http://i142.photobucket.com/albums/r94/kato--/4mm20plate20to20end20of20hub2028sli.jpg

Add or remove plates to get the desired height, if you measure it like this you need 4.5mm from the last plate to the edge of the hub.

[Capo]

From the manual

Fit the clutch plates in the following order:
- two driven plates 2mm thick
- driving plate 3mm thick
- convex plate 1.5mm thick
- set off six driving plates alternated with six driven plates
A driven plate should be the last of the clutch pack

[marchesini]

ok guys, appreciate the help and understand the theory behind everything so I feel cofident I can do this. Just to be clear, some more questions:

1. Assuming I need to add some some plates, where do i get them?

2. There are different thickness of plates. Can I buy them singly or does a pack include varying thickness plates.

3. Convex plates. I don't seem to have them. Are they unique to the slipper clutch (Bucci) and should I be looking for these as well. Will they make a difference?

4. Vernier. Good places to buy - preferably online as I have very little time at the moment. Unless some kind soul has one locally - Gary T, are you there? Actuallly, I just checked on fleabay, and they are not expensive. is this any good:
http://cgi.ebay.co.uk/TOOLZONE-PROFESSIONAL-VERNIER-CALIPER-GUAGE-150x0-02mm_W0QQitemZ310148083505QQcmdZViewItemQQptZUK_Me asuring_Tools_Levels?hash=item4836442f31&_trksid=p3286.c0.m14&_trkparms=65%3A12%7C66%3A2%7C39%3A1%7C72%3A1688%7C 240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50

5. If I need new friction plates - the bits with the pads on them - any recommended suppliers? BTW, they also look different to the ones on the Bucci slipper clutch images. My friction plates have a continuous surface whereas the Bucci reference images show several smaller pads on each plate. Does this matter?

I know a lot of this may seem obvious but I do not want to take it apart and then find I do not have the correct tools / parts to complete the job.

Thanks again for all your help.

Best

S

[fatbloke]

take the slipper clutch out and replace with the standard one, job done.

you've probably got a couple kicking round your garage

[marchesini]

take the slipper clutch out and replace with the standard one, job done.

you've probably got a couple kicking round your garage

Do you think that the problem is the slipper clutch though rather than the plates - or are they linked?

[fatbloke]

if you change the complete clutch the problem has to go away, have you got a stock
clutch?
after all how often do you need a slipper clutch from your house to the office?

[fatbloke]

slipper clutch (Bucci) and should I be looking for these as well. Will they make a difference?

4. Vernier. Good places to buy - preferably online as I have very little time at the moment. Unless some kind soul has one locally - Gary T, are you there? Actuallly, I just checked on fleabay, and they are not expensive. is this any good:
http://cgi.ebay.co.uk/TOOLZONE-PROFESSIONAL-VERNIER-CALIPER-GUAGE-150x0-02mm_W0QQitemZ310148083505QQcmdZViewItemQQptZUK_Me asuring_Tools_Levels?hash=item4836442f31&_trksid=p3286.c0.m14&_trkparms=65%3A12%7C66%3A2%7C39%3A1%7C72%3A1688%7C 240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50

Digital vernier gauge Maplins £10

[marchesini]

if you change the complete clutch the problem has to go away, have you got a stock
clutch?
after all how often do you need a slipper clutch from your house to the office?

I'll have a look in the garage - all three of my bikes have slipper clutches (I think) so in theory, there should also be 3 stock clutches kicking about somewhere? the plates though are the same - are they not?

Also slightly reluctant to take the clutch out on several factors:

1. you need a special (aka expensive) clutch holding tool
2. the more I take apart, the greater the potential to feck it up.
3. I'm an idiot and also lazy

And I use the slipper clutch ALL the time on my commute. Well, ok, never but on trackdays - a lot. I've had too many rear wheel locking scenarios on track that my bottom has never forgiven me for.

S

[slob]

Try to keep the rear wheel in the air to avoid those moments.

[fatbloke]

I'll have a look in the garage - all three of my bikes have slipper clutches (I think) so in theory, there should also be 3 stock clutches kicking about somewhere? the plates though are the same - are they not?

Also slightly reluctant to take the clutch out on several factors:

1. you need a special (aka expensive) clutch holding tool
2. the more I take apart, the greater the potential to feck it up.
3. I'm an idiot and also lazy

And I use the slipper clutch ALL the time on my commute. Well, ok, never but on trackdays - a lot. I've had too many rear wheel locking scenarios on track that my bottom has never forgiven me for.

S

answer your phone

[Capo]

You can tell the convex plate, it is thinner (1.5mm) than the other plates.
Stack height is important on slipper clutches and tends to reduce over time primarily
as a result of the loss of friction material from the friction plates.
The plates in a slipper clutch are the same as in a standard clutch.

Slipper clutches require periodic maintenance, (I do mine once a year). The slip action is caused by steel balls between two ramps on two halves of the clutch hub, as the 'back tourque' exceeds the clamping force which is a function of the clutch springs, the two halves rotate slightly this causes the balls to climb the ramps forcing the clutch plates apart, it is a modulating action automaticaly finding the correct position for the amount of 'back torque' vs the clamping force.
With use over a long period, the steel balls can groove the ramps causing them to stick.
The ramps should be inspected and greased.
Now did you find the instrument cluster yet :D