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Clutch Pin Snapped Again! Advice Needed

Discussion in 'Technical Help' started by HyperActivePaul, May 11, 2020.

  1. Hi all,

    Ive literally replaced the pin around 100 miles ago & its snapped again!

    any ideas what would cause this?

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  2. Unfortunately no. Do you think there may be something preventing the clutch pressure plate from lifting? I think you may have to look into that.
     
    • Useful Useful x 1
  3. Wow, that's a new one on me. Your 1st problem I put down to a manufacturing defect, but there's obviously something else going on.

    The Hyper has a cable actuated clutch with manual adjustment. You haven't got the clutch set up in such a way that when the lever is fully to the bar, the pin has already reached it's limit inside the engine and you are stressing it?

    Have you tried spinning the hub with a dial gauge to see if it's running true?

    Just a couple of thoughts, but genuinely just guesses.
     
    • Like Like x 1
  4. I did everything to the service manual including torques etc

    i had the clutch lever adjusted to spec so it had 3-4mm free play before actuation.

    Im stumped I really am....
     
  5. What would cause that??

    It felt absolutely super until it broke. Its as if its being pulled beyond it tolerance and breaking.....?
     
  6. I think the pin will take some abuse directly on its head with no issues. :thinkingface:

    I think once you begin to put a sideways load on it, this may cause it to snap. This was why I thought that there meay be something not runing true when the clutch / hub is spinning.

    Think of hitting the pin on the head directly with a hammer, and then hitting it sideways. I think hitting it sideways would cause it to snap.
     
    • Agree Agree x 1
  7. Yes i agree that there must be some sideways movement, the hub seems to have no play in it, everything looks ok & within tolerance.

    Im wondering if the lifter pin cam is putting the sideways movement onto the pin.
     
  8. I think I'd have a good look at that to see if it's true.
     
  9. Look at the end of the pin toward the top hat, its shiny like its been rubbing on something. @Robarano

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    #9 HyperActivePaul, May 11, 2020
    Last edited: May 11, 2020
  10. Is the release pin free to rotate inside the bore of the gearbox mainshaft?, as presumably the top hat on the release pin shouldn't be constantly rotating against the cam of the release arm when the clutch is disengaged, as it (and the pressure plate bearing inner race) would come to rest. If something is causing the pin to rotate when the clutch is disengaged then that might put an abnormal side load on pin resulting in the failure at its weakest point.

    I guess there would be some initial rotational contact between the two parts as the pin would be rotating at the same speed as the mainshaft due to friction, so there would be some evidence of rubbing between the two parts.
     
  11. The pin is pressed through a bearing that does spin freely with no issue.

    Its very hard to think what may be causing this issue.
     
  12. Do we have a Ducati mechanic on the forum at all???
     
  13. There are a few who think they can do it..
     
    • Funny Funny x 2
  14. OK, just wondered if there was anything preventing the pin from spinning when the clutch was built up. As it’s now disassembled it’s also difficult to see if the pins were running concentric with the main shaft.

    You noted there was some axial movement on the actuating arm which looks normal, is there any movement in any other directions, especially at the blind end of the arm, and that nothing appears to be missing/broken from the cam on the actuating arm, obviously difficult without a new one to compare.

    There must be something putting an abnormal load on the pin.

    Hope you get it sorted out soon.
     
  15. the pictures certainly help, in the middle picture, where the cut-out relief shows like an inverted "U" against the Blitz paper backdrop. It would be good to see a view with shaft rotated approx 90 degrees to show the base of the "U" as regards "shininess"/wear (if possible).
     
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    • Thanks Thanks x 1
  17. The pin was pushed all the way in untill touching the inner race of the bearing it sits in, it physically couldn't be pushed in any further to allow it to stick further out for the fork to grab it etc....

    It took around 150 miles to break it, you would expect it to break instantly if major issue?
     
  18. I checked everything for play and wear & couldn't feel or see anything that screams replace me. The pin spun freely in the bearing. It all went back together like a dream. Rode perfectly untill it broke AGAIN :weary_face::weary_face:
     
  19. One more try - Is the spring (item 17) OK so that actuating arm is correctly tensioned and is not free to rattle around and fret against the pin when the clutch is engaged?

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