Clutch help

Discussion in 'Motorized Bicycle General Discussion' started by fx-2, Apr 29, 2012.

  1. fx-2

    fx-2 New Member

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    Finished the bike today started right up . The motor put out to much torque for the clutch . I need more clamping pressure . The clutch has been adjusted the right way the wrong way and the main spring in the center of the housing adjusted also . I know there are motors that made more power that run this clutch . What do you guy do to them . Spec. on motor and bike .66 cc jet ,mild port work 1 mm wider intake an exhaust .5 mm higher . Cylinder an case matched . Piston .5 mm cut at transfer port , intake cut to size of port on piston skirt . Head cut .5 mm to up compression . Carb is Dellorto sha 16-16 , Jaguar cdi box . A pipe set to run in 3500-7000 rpm range . The rear sprocket is a 44 . The people helping me on this project have owned built motorized for some time so the clutch was adjusted right , all the part are in the right place . Thanks Dan P.S. I did a search first
     
  2. 2door

    2door Moderator
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    Are the clutch friction pads possibly dirty/glazed/oily?

    Tom
     
  3. rustycase

    rustycase Gutter Rider

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    I would not think a chinagirl could be built to exceed the capability of the simple clutch, if it is properly set up. Of course I've been wrong before, but it does not seem like the mods mentioned put the motor at the top of the HP scale.

    As 2door said, perhaps the pads are not in tip-top condition.
    Or, the metallic friction surfaces have become glazed or oily.
    Perhaps the actual clutch spring is weak, or could be tightened more, or shimmed for increased pressure.
    Is the clutch cam releasing completely?

    Is the gearing far too tall for reasonable take-off expectations?

    Are the rotating engine components turning freely?

    Good luck
    rc
     
  4. rustycase

    rustycase Gutter Rider

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    xx
    double
    deuce
    doble
    kill it!
    :)
     
  5. fx-2

    fx-2 New Member

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    This is what I've done . Adjusted the flower nut clock wise didn't help . Did that 2-3 times to the point the clutch would not release . I removed the flower nut and cover to check for grease in clutch it was clean . The clutch pads were starting to glaze on the inside the pressure plate looked new ,clean the parts lite sanding of pressure plate an put it back together . No help . Next tighten the spring in side 1/2 turn of adjuster nut . No help . Might be just a bad clutch . Thanks all Dan
     
  6. fx-2

    fx-2 New Member

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    I think I should note that every on this bike would not work the first time every thing ! So this does not surprise me . So this probably some thing odd . Just for reference I was a heavy duty mechanic welder for 25 yr work every thing from chain saw to D-9 Cats . Thanks Dan
     
  7. 2door

    2door Moderator
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    I'm curious. You said "the motor started right up" then you go on to say, " the motor put out too much torque for the clutch".

    What do you mean by "too much torque" ? If the engine started, how did you start it? By pedaling and engaging the clutch? If so, the clutch must have held tight enough to turn the crankshaft. What are the sypmtoms you are having? Does the clutch slip after the bike is rolling and you apply power? If this is the case then I'm going back to the clutch pads slipping when hot. That is due to oil/glaze.
    Do you know the proper procedures for adjusting the flower nut? There are several good tutorials here for doing that.

    Tom
     
  8. fx-2

    fx-2 New Member

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    After thinking about for bit I didn't check the pressure plate to see if it was flat . Well check that out next . Dan
     
  9. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    Also, adjusting the "flower nut" doesn't help with spring pressure. You have to do that by tightening the threaded collar inside the cases on the shaft.
     
    #9 Bikeguy Joe, Apr 30, 2012
    Last edited: Apr 30, 2012
  10. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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  11. fx-2

    fx-2 New Member

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    It was started by pedaling about 20 feet clutch out an started right up every time . It slips under power . Yesterday when there were two other MB at the shop it was so much snapper on the throttle an rev quicker than the other 2 . I had a friend do all the test rides , he been riding these thing for 4 years . As per him this smoothest no vibration ,torquest he been on . Dan
     
  12. fx-2

    fx-2 New Member

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    I tried a adjustment on the main spring inside the case tighten 1/2 turn didn't help . Dan
     
  13. fx-2

    fx-2 New Member

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    So you have the complete picture . This motor was disassembled new bearing new gaskets an seals . The only work on the clutch was the bucking bar was polished on both ends and a small radius put on cam end I mean very small 1/16 R maybe . The cam surface was polished . Ever thing was cleaned with solvent then final cleaning with brake cleaner on assembly That's all . And red grease on the bevel gears not a lot . I check the other thread not much help . Thanks for all the help . Dan
     
    #13 fx-2, Apr 30, 2012
    Last edited: Apr 30, 2012
  14. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    How much resistance is at the lever. I would tighten the spring until the lever pull is on the border of "tight" for your personal tastes, then give it a shot.

    Finally, are the clutch pucks free floating or are they tight? They should be able to move freely.
     
  15. fx-2

    fx-2 New Member

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    I start tightening the spring . I'll go 1/2 more turns . You can take the pucks out with fingers they are not tight . Thanks Dan
     
  16. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    Alright.

    Keep us posted.

    P.S. I had to turn one 3 turns and it was just enough.
     
  17. rustycase

    rustycase Gutter Rider

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    Yup!
    I agree with Joe.
    Tighten up that internal spring adjustment until it works.
    ...I don't think the radius on the cam was such a good idea.
    They work easy enough... you have only limited the amount of throw you have control over. I would undo that mod...
    Good luck with that little beastie!
    From what you say, it's gonna be a lotta fun when you get it dialed in!

    Best
    rc
     
  18. 2door

    2door Moderator
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    Actually, RC, smoothing and polishing the clutch actuator mechanism is a mod I do to every engine I work on. The reduction in clutch pull is significant if done right. I smooth and even polish the contacting parts on a bench buffer then lubricate well before reassembly. Naturally, if one gets carried away they could remove too much material and compromise the mechanism but a simple radius on the edge of the cam will not hurt. In fact it should have been done at the factory.
    Tom
     
  19. Goat Herder

    Goat Herder Gutter Rider

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    I agree Tom that little correction has made a big difference over here too. One of my buddies showed that to me.
     
  20. fx-2

    fx-2 New Member

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    I have a clutch now . The clutch cover on the Jet motor is not dished as much a Grubee The nut holding the clutch assy. to the jack shaft was not all the way tight . The clutch cover was held up by the nut an the clutch slipped . Tighten the spring 1 1/2 turn . It work good now . Thanks all for your help . Dan
     

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