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No Drive - Clutch Stays Open..

Discussion in 'Supersport (1974-2007)' started by =^..^=, Jan 21, 2022.

  1. Ok - Carby 94 ss900
    Replaced the clutch basket / centre / plates with this

    https://www.ebay.co.uk/itm/18307657...29692X874039X15deb16c6b924849a0c3be16826330be

    It worked quite happily on the stand and for a couple of laps around the block - put all the bodywork back on, went to go for a spin, pulled the clutch in, first gear, released clutch and there was no drive.
    Back in garage, fairing off, cover off, caps / springs off, pressure plate off - as I removed it the push rod came with it. I replaced the clutch centre at the same time as the old one had hole in it (but looked like it shouldn't) - with the old centre the push rod stayed in place, not attached to the pressure plate...
    Pushed the rod back in, pushed it back into the master cylinder, re-assembled the clutch (left the cover off)
    Fired engine up, clutch worked fine, put cover back on, put fairing back on, rode bike out of garage, up the road and the clutch again would not engage so no drive...

    Thoughts ? Put the old clutch centre back in ??
     
  2. did you line your notched spring post up with the notches on the pressure plate ok?
    The first picture shows pressure plate out by one post:-

    [​IMG]
    [​IMG]

    I hope you can see the enclosed picture, struggling to get it to post..
     
    #2 Chris, Jan 21, 2022
    Last edited: Jan 21, 2022
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  3. It's a different clutch centre to that - I couldn't see a notched post but I did line the notches up and the lined up the notch on the pressure plate clutch_1.jpg clutch_2.jpg
     
  4. I did line up all the grooves but I'll mark a post just to be on the safe side...
    I might have put the spring spacer in backwards though..
    I'll put the old centre back in too and give it another go..
    I was thinking for the last couple of hours "have I bought the wrong clutch" so thanks for the comments, I feel a lot calmer now
    Cheers!!
     
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  5. I guess you will not put clutch cover and fairing on for the next test - I will try and find pictures but you can see looking down at assembled clutch when sitting on bike if all is ok - when you pull clutch in, watch the action and make sure plates return and get clamped upon clutch lever release - you only needs 2mm of movement for normal operation - i.e. 2mm is more than adequate.
     
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  6. Nope... Learned that lesson tonight!!
     
  7. It's laborious, but if you aren't happy with alignment markings then you can carefully slide pressure plate on and off to determine if plates are "in repose" when pressure plate engages with them*, this is much easier if you remove pushrod but if it's solid in spigot bearing then I understand. There should be no effort to engage pressure plate with fitted plates, ditto withdrawal, look for how even the pressure plate hole clearance is for the spring post*, if it touches on one side with a large gap on the opposite side then move on to the next tooth..


    *this is with all plates fitted, last operation before you start to put springs and caps on etc.
     
    #7 Chris, Jan 21, 2022
    Last edited: Jan 21, 2022
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  8. I didn't see the rest of the post on the 37 teeth.. it's been one of those nights..
    I've marked the centre, I'll put all the notches in line with that and I'll line the pressure plate notch up with it too.
    Careful re-assembly tomorrow as enjoying a whisky and a cigar now.. IMG_20220121_215555641.jpg
     
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  9. :upyeah:that's got to be it hasn't it? :upyeah::upyeah: - can hopefully move on to the next possibility :)
     
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  10. thanks very much for your help - and cheers !!
     
  11. Just for reference: – the notches on the plates don’t have to be aligned with anything, slight controversy as per many Ducati things, I think they are there to initially show alignment in case wear patterns need studying for any reason.
     
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  12. Ok, worked out what was happening. The pressure plate was being lifted off the drum, turning a fraction and ending up sitting on the drum...

    When I found this I flipped the pressure plate over and you can see scores in the anodising... I've not looked closely at the oberon plate before but the teeth that engage with the drum are not all the same - one of the sections has two notches, the rest have one and the two engangements either side of that are angled... (see below)

    Put the stock plate on and that works fine...

    Would obviously prefer the oberon plate as it looks nicer through the vented cover so if anyone can shed some light on this... It might just be incompatible with the new clutch...

    oberon_pressure_plate.jpg
     
  13. glad you posted the pic of that pressure plate, a couple of things come to mind, i've never seen a pressure plate with so few corresponding engagement slots for the clutch plate teeth to bear against, I don't think it's a good idea to have so few (areas of engagement). Have you tried laying a clutch plate on that cover to see if it nests nicely? I wonder if the p.p. is meant for an "even" number of teeth on the outer diameter. Also - scratching my head here, there are no easily visible shoulders* in the clutch spring holes for the lower spring cap to bear on? perhaps only visible from the other side.



    *EDIT I think I see them, just a bit "slender"..
     
    #13 Chris, Jan 22, 2022
    Last edited: Jan 22, 2022
  14. Obviously the pressure plate is lifting clear of the clutch drum/centre when you pull in the lever.
    I think that you need to reduce the deck height of the plate stack to make it work.

    Steve R
     
  15. Unless the crucial dimensions differ between the two pressure plates, it shouldn't make any difference as same plates used and worked ok with other pressure plate.
     
  16. Exactly it sounds to me that the after market plate has different dimensions to a OEM plate.

    Steve R
     
  17. Agree, haven’t they often.. pain in the backside, looking back at posts on this forum, the majority of problematic clutch posts are dealing with the incompatibility of aftermarket parts. Over-powerful stainless steel springs is another.
     
  18. Just for clarity - I fitted the oberon plate a little after getting the bike so it has done some miles with the old worn clutch basket / drum / plates.

    I think the oberon teeth are maybe just slightly "shallower" which when it lifts is allowing it to lift over the new drum. Maybe when the plates are worn it will be ok but right now it's not. Next time I have the ducati pressure plate off I'll get a depth gauge and measure the two "side by side"

    It's running fine now with the old pressure plate so I'm ok with it - maybe in a couple of hundred miles I'll swap the oberon back in and see if it works then - maybe it just needs a touch of newness rubbing off the drum and plates.

    Thanks for your help guys - we have a nice outcome here :)
     
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  19. I'm with you on that Chris, I can't see that being a good for longevity of the teeth, and really goes against what I thought about Oberon parts.
     
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