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Ducati 916 Clutch Problem

Discussion in 'Technical Help' started by ChrisDS, Mar 14, 2017.

  1. Yesterday took my 916 out for a blast and it was working perfectly.

    Today I rolled out my drive onto the sloping road and as I let my clutch out.....nothing.

    Nearly killed myself pushing the bike up the road and up my driveway, then tried bleeding the clutch system as I though there could be some air. No air found. Took the clutch cover off and noticed this.....
    [​IMG]

    I removed all the plates and spacers and it all looked ok. Replaced them in the same order and the clutch now seems to work again.

    Anyone got any idea what could cause this?
     
  2. yes, your 'stack' is slightly too high, if you search on this or the ducati.ms Forum you will see many references to this. The 'stack' dimension is the combined height of all the plates one on top of the other and if the figure is above the 'recommended' figure then the last (friction) plate can pop out of it's location in the basket. You can go through all your plates to see if you have a thicker plain/steel plate (for example) and replace it with a more common thinner one if you have some spare. The measured stack is not as critical as it sounds but is a good base guideline to start off with, you can just examine the last plate by eye as you pull the clutch in and check that you can't dislodge it by hand - Watch your fingers though!
     
    #2 Chris, Mar 14, 2017
    Last edited: Mar 14, 2017
    • Agree Agree x 1
  3. This is what it looks like now...

    [​IMG]

    Does this look acceptable?
     
  4. Sorry our posts crossed.

    Thanks for the advice. I'll have a see if I can dislodge it.

    I do have a few miles on this clutch and I haven't experienced any problem before. Although, saying that, the bike has sat for many years and I was wondering if the spring strengths could have reduced significantly over that time, making this issue more likely.
     
  5. Maybe the pressure plate wasn't pushed in fully
     
  6. I just checked the plates;

    2mm Plain
    Friction
    2mm Plain
    Friction
    2mm Plain
    2mm Plain
    Friction
    ... etc

    My Haynes manual says that you start with a 2mm plain and then a 1.5mm plain, then friction/plain/friction/etc.

    It looks, on the face of it, that the plain plates have been fitted incorrectly.
     
  7. yes, just about - sometimes end plate can dislodge just by chance when stack is close to top dimension.
     
  8. he hadn't stripped it, found no clutch when went to ride after all working well during ride before.
     
  9. It isn't critical to have exactly the right order and nor is it a big problem to have your stack height a little low. As you've found, it's much worse to have a stack that's too high.

    My stack height is seriously low and it doesn't slip at all. However, the reduced pre-load on the springs does make it deliciously light.

    Cream Revenge has a slipper clutch and stack height is apparently pretty critical on those.

    While you're playing with the stack height and trying to reduce it, you could try the quiet clutch mod, which will make your clutch last a lot longer, as well as making it quiet.
    Simply put one of the friction plates in first and then order the plates alternately with two plain plates at the top and a plain plate and the thin dished plain plate together somewhere towards the bottom. Putting the friction plate in first allows it to sit down into the curved section at the bottom of the slots, thus effectively reducing the stack height and allowing the tabs to jam in to rounded bottom of the slots.
    This stabilises the whole pack, preventing it from oscillating and cutting both noise and wear.
    Win (reduces your stack height)
    Win (reduces noise)
    Win (reduces wear)
    Win (saves money spent on replacing friction plates and baskets)
    Win (saves work replacing friction plates and baskets)
    Win (will make your clutch a bit lighter)
     
  10. Well I think I may have fixed it. Whoever fitted the plates put them in wrong!!, and it's something I've never checked before.

    As it's an SP I have eight friction plates. Now the sequence goes,

    2mm plain
    1.5mm plain
    friction
    2mm plain
    friction
    2mm plain
    friction
    2mm plain
    friction
    1.5mm plain
    friction
    1.5mm plain
    friction
    1.5mm plain
    friction
    1.5mm plain
    friction
    1.5mm plain

    Total width : 38mm
     
  11. Not sure why the stack height will have changed with the new order and won't having a thin plate at the top make it easier for it to pop off??
     
  12. Right, this adds to my picture! Thanks for the info.

    (BTW, I too have a slipper clutch.)

    Someone had done that 'quiet' mod, having a friction in first, and two plain together within the stack. The problem was that there was only 2mm at the top so the first friction plate was a little too high, hence the issue.
     
  13. Having two plain at the top (next to the pressure plate) means the first friction sits lower down, if you get what I mean
     
  14. My stack height is in the low 30s and I get no slip.

    I do have a 2-finger clutch though ... :)
     
  15. The first friction plate can only sit lower down if it goes in first. If a plain plate goes in first, it will sit on top of it.
    Yes, if the plain plate is thinner, the first friction plate will be that much lower but the overall height will add up to the same.
     
  16. I have no wish to muddy the waters but how many of your plain 1.5mm plates have a very small dot peened into the tang next the cut out on the outside rim ? If it has a dot it's a dished plate which some clutches work with 1 and some with 2. I think you need to discard the extra 1.5mm disc for a pack height of 36.5mm and for personal preference I agree with Old rider, I'd start with a 1.5mm plate and finish with a 2mm plate. At the end of the day, if the clutch works, go with it. Andy
     
    • Thanks Thanks x 1
  17. Good point...
    Definitely needs to be checked.

    38 mm is not high either
     
  18. The dots are hard to spot.

    Look at the middle of the base of the tooth adjacent to the half-moon cut-out.
    If there is one, it's a tiny punched dot on one side only.

    EDIT: Oops Andy already said where to find it...
     
    #19 Old rider, Mar 14, 2017
    Last edited: Mar 14, 2017
  19. Yep, seems I have an extra 1.5mm plate in there which I will now use as a wall ornament.

    I think I'll go back to the 'quite' mod., starting with a friction as I liked it quiet and it seems to make sense. I had no idea that it was that which was making my clutch quiet, I thought it was due to it being a slipper. (but what do I know???)

    I'll check for the dots, none of them seemed to be 'dished', but I have read that they flatten out in time.
     
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