clutch shaft replacement/adjustment help?

Discussion in 'Transmission / Drivetrain' started by jatgm1, Jul 26, 2016.

  1. jatgm1

    jatgm1 Member

    i have a 66cc grubee skyhawk engine, and i and trying to figure out how to adjust or replace my clutch shaft. my clutch wont grip right, when i try to engage the clutch, the clutch slips, no matter how much i adjust the flower nut or cable. also, the bucking bar is sticking out much more than it is normally does, considerably more.

    in FACT, when i adjusted the clutch the point where it would grip enough to sorta start, when i let go of the clutch lever, the cable wouldnt retract all the way!

    from what i understand there is a spring on the clutch shaft inside the engine, and that spring needs to be adjusted properly to provide enough pressure to for the clutch to grab. i think that there isnt enough pressure. but im not sure.
    i thought there was a problem with the clutch because when i watched the clutch spin in looked cock-eyed, as if the clutch was bent or the balls in the clutch were shot, and replaced it, but i literally just replaced the clutch, the entire assembly. like i replaced it, and then when it didn't work i came on here to beg for help of the pros, because the clutch wont grip, the the cable wont retract all the way, the clutch/clutch shaft looks cockeyed, and the bucking bar is too far out. anyone with a video showing h0w to adjust the clutch shaft properly?
     

  2. jatgm1

    jatgm1 Member

    also, i took the plate to the clutch off (where the bucking bar is) and the bucking bar is not longer sticking out that much, i think adjusting the flower nut fixed that part. everything else is still a problem.
     
  3. crassius

    crassius Well-Known Member

    step 1 - with lever released, adjust cable for tiny bit of slack
    step 2 - with lever locked, loosen flower nut until bike rolls freely with no drag on small gear - tighten flower nut one notch and see that it now drags a bit, then re-loosen that one notch and lock it
    step 3 - release lever and recheck cable slack

    this will give you a properly adjusted clutch - if it fails to grab, then pads may need cleaning or lever may be bad

    note that the amount of grab available to the clutch is controlled by the distance between the locked and unlocked positions of the lever - on some longer levers, this distance is way too short, but can be fixed by filing down the housing so that the lever moves farther away from handle bar when released
     
  4. jatgm1

    jatgm1 Member

    from everything i can find and after looking at it again after thinking, the obvious answer dawned on me, i lubricated everything when i installed it. if thats the reason why im having problems then some brake cleaner should take care of it. ill update when i try. thanks.
     
  5. FurryOnTheInside

    FurryOnTheInside Active Member

    I have not got my cable (or engine) on yet.
    But the clutch plate pressure is adjustable by the internal spring's preload nut. This is accessed by removing the clutch cable stop (where the cable outer (sleeve) sits) and putting a flat screwdriver in the hole to push the preload nut around.. Forwards toward the cylinder while holding the clutch plate or sprocket still.
    The clutch plate could perhaps be improved with some score marks as the knurled surface isn't very rough, but I believe this is secondary to the preload nut adjustment.

    The clutch plate need only separate from the pads by 2 millimetres when the clutch is opened/disengaged and the clutch plate on mine was no longer "cockeyed" once the flower nut was adjusted to give the 2mm seperation.
     
  6. jatgm1

    jatgm1 Member

    thats what that hole is for...
     
  7. crassius

    crassius Well-Known Member

    never seen an inner spring need adjustment in many years - certainly would not recommend messing with it on any motor made less than 5 years ago
     
  8. jatgm1

    jatgm1 Member

    okay, so that nut was so far to the right side that when i looked i could hardly see it, so i got a really long and skinny screwdriver and held the nut while i turned the wheel until it was to the left enough. then threw some gear oil in the hole to lubricate it, and put everything together again.
     
  9. jatgm1

    jatgm1 Member

    i took this whole damn thing apart so thats probably why the spring is a bit off. not to mention the kit was cheap as dirt on ebay. i already replaced the bucking bar, the clutch, the entire top end, the carb, the fuel line, the fuel filter, the fuel petcock (hose barb adapter), alot of screws, the whole clutch arm, the throttle, the cdi, magneto, spark plug, and all brake lines except the clutch one until about 30 minutes ago, when i just changed it, except with this one i left the housing too.
    point being the fact that this thing was either
    A not adjusted right at the factory or
    B accidently changed by me when i was working on it
    isnt all that surprising to me, i just didnt know that i could adjust it without opening the entire engine up again and every time i open it i put new gaskets so i just didnt wanna deal with that. lifesaver.
     
  10. FurryOnTheInside

    FurryOnTheInside Active Member

    Have you been able to test it yet?
    I am worried about the oil now. There is a risk that it will leak out onto the clutch pads. There is supposed to be grease in there but oil sounds like a bad idea to me. :( Sorry. I know that it would be a real pita to clean it out now but it'll be worse if it gets to the pads. I know you don't want to disassemble the whole thing again. Maybe just leave it tipped over onto its left side overnight and if there is any excess oil it can run that way and be mopped up from the bucking bar/sprocket area...
     
  11. jatgm1

    jatgm1 Member

    the oil is in the hole under the brake cable holder. basically onto the spring. and its oil for my yamaha zuma's transmission, so its thick, also, the spring is really tight now so i dont think that a little slippage is an issue, my problem was originally that i could rev it and not move the bike. i can deal with a little slippage until the oil burns off. and i didnt get to try it, but i have work soon so im going to test it before i leave and if it works just take it to work.
     
  12. jatgm1

    jatgm1 Member

    ok, so i tested it, and it works, but slips just a tiny bit, also on an unrelated matter i realized the exhaust has a smaller output than the one i got with the kit, so i drilled out the exhaust a little, plus this needs the right size jets and an idle screw since i lost the one that came with it.
     
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