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Thread: No Clutch Freeplay on K75

  1. #1
    Rally Rat
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    No Clutch Freeplay on K75

    I've been a part of an unresolved discussion at http://www.motobrick.com/index.php?topic=4439.0

    Capture.JPG

    Carl and I have K75RT bikes and after transmission maintenance and reassembly we've both found it impossible to get clutch freeplay using the recommended procedure.

    It seems that with new clutch cables installed in the most relaxed configuration (adjustment screw on hand lever in all the way) resulting in a ~90mm cable length at the cable bottom, then the clutch lever #7 is already touching the piston/bearing/pushrod #1,2,3 even without the adjusting screw #10 installed.

    If the screw on the hand lever is unscrewed a few turns as recommended so that the exposed cable bottom length at the clutch lever is set to the recommended 75mm then the clutch piston/bearing/pushrod is depressed enough to perhaps slightly disengage the engine from the transmission.

    What are we missing?

  2. #2
    Benchwrenching PGlaves's Avatar
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    Check the lengths of the old and new cable sheaths. Are they the same?

    Most importantly, compare the lengths of the difference between each sheath and the cable within it. That is, how much longer is the actual cable than the cable sheath. Those comparisons will tell you if differences in the cables account for the difference. For example, if you have 6 inches of exposed cable length on the old and 5 inches of exposed cable on the new one - bingo.

    If there are no differences then you need to consider what changed in the clutch assembly.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://www.bigbend.net/users/glaves

  3. #3
    Rally Rat
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    Thanks, Paul.

    With about 90mm of exposed cable length at the bottom (spec is 75mm) it feels like the engine is engaged to the transmission 100%.

    If I adjust the screw at the hand lever at all, even a couple of turns, the push rod is depressed enough to disengage the engine from the transmission some.

    If I adjust the screw at the hand lever so that the exposed cable at the bottom is to spec (75mm) then the transmission is disengaged entirely from the engine.

    This is the case with the #10 screw just barely protruding through the threads in the clutch lever.

    It's weird.

  4. #4
    3 Red Bricks
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    I believe that your problem (and the other guy's on the motobricks forum) is that you are measuring to the wrong surfaces.

    The measurement is SUPPOSED to be from the end of the metal on the sheath to the BARREL on the end of the cable (Not to the swage on the end of the cable).

    With the lever end completely disconnected the cable should have about 125mm from the end of the sheath to the barrel:

    cable 2.jpg


    Properly adjusted, it should be 75mm between the same two points:

    cable 1.jpg




    Last edited by 98lee; 06-16-2013 at 05:07 PM.
    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  5. #5
    3 Red Bricks
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    OR

    You have an incorrect cable that has this dimension less than 24mm:


    cable.jpg



    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  6. #6
    Rally Rat
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    Thanks, Lee.

    I was measuring it properly. When installed the max possible sheath to barrel distance is about 90mm. If I adjust that using the hand lever screw even a little, the clutch lever starts to depress the push rod.

    I'm in the process of removing the transmission from the bike now so we'll see how things look.

  7. #7
    Rally Rat
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    Here's what the lever-to-piston point looks like at rest.

    The piston is inserted "finger tight". I suspect it should be flush with the housing?

    P1020906.jpg

  8. #8
    3 Red Bricks
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    Not supposed to be totally flush. Can't get you the correct dimension until tonight or Monday.

    Looks like end of push rod is not going inside throwout bearing or throwout bearing is defective.
    Also look for bent clutch push rod or push rod not going fully into hole in spring or end of crankshaft. You didn't change pushrods did you?

    Did you see my post just before your last one?


    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  9. #9
    3 Red Bricks
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    Quote Originally Posted by timtyler View Post
    Thanks, Lee.

    I was measuring it properly. When installed the max possible sheath to barrel distance is about 90mm.
    Measure it with the lever end completly disconnected and the cable not going through the adjuster. You should get 125mm.


    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  10. #10
    Rally Rat
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    Lee,

    The metal sheath measurement in post #5 is the same for me.

    My push rod is perfectly straight.

    P1020907.jpg

    P1020908.jpg

    P1020910.jpg

  11. #11
    Rally Rat
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  12. #12
    Rally Rat
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    Pulled the clutch pack and cleaned it up. Friction disk is exactly 5mm thick.

    Center hole in clutch housing is clear.

  13. #13
    Rally Rat
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    I mounted the friction disk by itself on the transmission input splines and spun it.

    It did not show any signs of being warped or uneven.

  14. #14
    Benchwrenching PGlaves's Avatar
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    I think the problem is at the back of the transmission where the throwout bearing interfaces with the clutch rod. I think it is hanging up and not engaging the rod correctly.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://www.bigbend.net/users/glaves

  15. #15
    Rally Rat
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    I've buttoned almost everything back up and the throw-out bearing as maybe 1mm more recessed in the transmission, but not much.

    P1020917.jpg

    I was extra careful center-aligning the clutch pack. It's a straight shot all the way to the drive shaft.

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