Centrifugal centrifugal clutch stuck in motor mode no neutral

Discussion in 'Transmission / Drivetrain' started by CorpralFever, Aug 25, 2008.

  1. CorpralFever

    CorpralFever New Member

    :confused: well here is what happened I took my bike on a 7 mile trip one I have taken alot and when I got there my manual clutch did not work no nutral the only reason my bike was still running was the centrifugal clutch was still working. I allwas rode my bike like there was no centrifugal clutch useing the manual clutch at every stop. since I do not understand how the clutch works I can't track down the problem. I took off the centrifugal clutch to get to the manual one and plate pushes off with clutch arm fine pads are a bit worn but ok and spring under plate is fine. maybe if I knew a bit more about how the clutch worked I could track down the problem. I know that the plate pressing down on the pads grabs but the plat is atached to the weel that is attached to the gear on the centrifugal clutch that is attached to the crank shaft so I don't understand how the clutch plate grabing makes the weel spin when the crank shaft is allready attached to it lololololol can someone explain in detail how this works and give me some idea ( SRY about spelling) what to look for thanks
    O ya its a HT 66cc
    Last edited: Aug 25, 2008

  2. graucho

    graucho Active Member

    Start with the clutch arm on the left side of the bike. If you push the arm
    all the way in manually tward center and push the bike what happens? Did the clutch cable loosen at
    the arm, so when you pull the clutch in the cable dosen't pull the arm inward far enough?

    Attached Files:

  3. CorpralFever

    CorpralFever New Member


    yes I have pushed clutch lever by had all the way in and still no nutral. clutch lever feels normal. I think maybe someting broke inside the motor caseing but im not sure how to take it all apart :(:shock:
  4. spad4me

    spad4me Member

    Is your clutch cable worn out
    Mine ate through the plastic liner soon after I started using it .
    A Wall Mart replacement cable fixed the problem.
    Move your clutch arm with your hand or a pair of vicegrips..
    Does your clutch disengage?
  5. arceeguy

    arceeguy Active Member

    I didn't know you could have the centrifugal clutch AND a manual clutch!
    I ordered a centrifugal clutch kit and recoil start to go along with my HT engine. The clutch kit specifically stated there were no instructions, and the end user had to figure everything out on his own. But looking at the picture, it looked like the big gear with the clutch pads gets replaced with the centrifugal clutch assy and the manual clutch was removed. Since I don't have my kits yet, I'm not sure how this works,but I guess I'll find out! I bought the recoil start figuring that would be the only way to start the engine because of the loss of the manual clutch for bump starting. Oh well.....
    Last edited: Aug 26, 2008
  6. CorpralFever

    CorpralFever New Member

    no spade4me its not the cable. Allready made sure of that. thanks tho :) allso forgot to mention during that ride at one piont it sounded like I ran over a peace of spring steel but looked back and seen nothing. Arceeguy you will still have use of maual clutch and can still pedal start it too :)
  7. CorpralFever

    CorpralFever New Member

    I think this might be it


    these two plates are they ment to move freely from each other mine do not?

    took the whole thing off holding it in my hand and they will not turn freely from each other could this be it I hope so easy to fix i think do they come apart from each other?:smile:
  8. CorpralFever

    CorpralFever New Member

    ok fixed it

    well that was it. I had anouther motor an 80cc in my garage that just wont start so I took the flyweel off that one and used it on my 66cc it was just a little loose on the shaft but worked and now im riding again. Not sure what went wrong to freeze up the other one I will try to get it apart and see what went wrong. Do you think it was becuz I clutched it like normal? any ideas would be helpfull thanks to every one who replyed also I hope this post helps someone having same problem :shock::grin::grin::grin::rolleyes:
  9. arceeguy

    arceeguy Active Member

    I'm glad you found out what the problem was! I will make sure that those two parts move freely within each other.

    I just got my HT engine with centrifugal clutch kit, and now I know how you can have both a manual clutch and a centrifugal clutch - without a recoil start! Very clever engineering, but it does make the engine a bit wider. Was there a problem with the pedal cranks clearing the clutch/primary gears?
  10. CorpralFever

    CorpralFever New Member

    had to bend my cranks

    Yes the motor is wider and I had to heat up my cranks and bend them to clear the motor do both sides for balance :)

    Attached Files:

    Last edited: Aug 28, 2008
  11. CorpralFever

    CorpralFever New Member

    by the way I did find out what froze the two parts together after awaile ruber shavings from the clutch pads will get inside there are 52 bbs for berings in there and they need to be oiled about every 300 miles or so if you use a gear puller to pull the flyweel off there are 3 holes on the back one drop of oil in each one or a little grease will keep them from freezing up :)
  12. QuadManiac

    QuadManiac Member

    FYI with the centrifugal clutch and the pull start the engine is 6 7/8" wide... the typical wider cranks and shaft (the ones u get from Sick Bike Parts with the jackshaft kit) get you to about 6 5/8", not quite enough.

    RE: failure of the centrifugal clutch - those balls are part of a one way bearing that still allows the motor to be started via the standard clutch and rear wheel motion without the centrifugal clutch shoes engaged, but normal centrif clutch action when the motor is running... this one-way likely seized due to the debris you described.
  13. arceeguy

    arceeguy Active Member

    Great information guys, Thanks!

    Centrifugal clutches on HT engines aren't really that common yet, so any information is sorely needed!

    I will run my HT engine "as is" with the manual clutch for now. When I get wider cranks, I will install the CC kit and see how she runs!
  14. oreilly907

    oreilly907 New Member

    this thread saved my life. Thanks Graucho. A pircture is worth...
  15. Jonathan Silva

    Jonathan Silva New Member

    I need help with my centrifigural clutch

    HI guys i have a 66/80cc sky hawk 2 stroke engine that im ordering a centrifugal clutch for can u guys give me any idea of how to install it and how exactly it works , thanks very much appreciated.
  16. Fabian

    Fabian Well-Known Member

    Do a Google search for:

    "Centrifugal Clutch - 48cc, 60cc, 66cc, 80cc - pull-start/pedal-start, 2 stroke"

    and also for:

    "Lubrication port > Modified Centrifugal Clutch - 48cc, 60cc, 66cc, 70cc, 80cc - pull-start/pedal-start, 2 stroke"

    and also for:

    "Pull-start, Pullstart, Pull Start, 80cc, 70cc, 66cc, 60cc, 48cc,"
    Jonathan Silva likes this.
  17. Jonathan Silva

    Jonathan Silva New Member

    ok im looking them up am i still gunna need to use my manual clutch lever to pull strt the bike or will it work if i just pull on the pull start with a centrifigural clutch
  18. Fabian

    Fabian Well-Known Member

    The photos will explain everything, but in short, you will not need to use your manual clutch if the centrifugal clutch is working properly.
    Use your pull-start to start the engine or pull in the manual clutch and drop start the engine if you have a single speed drive system.

    If using a shift kit, it's just as easy to pedal start the engine as using the pull-start.

    The centrifugal clutch needs to be modified to give good reliability, as per the photo tutorial.
    Jonathan Silva likes this.
  19. Jonathan Silva

    Jonathan Silva New Member

    thanks for your help when i get it in i shall us the photo tutorial to help me this is my first centrifigural clutch im doing im doing it on my bike before i do it on a customers this way i have it dwon when that time comes thanks for ur help if i have more questions when the time comes i will ask.. i can take my clutch lever off my bike once i put the centrifigural clutch in right and just leave the orginal cluth engaged ?
  20. Fabian

    Fabian Well-Known Member

    Yes and no

    Yes you can take the clutch lever off the bike because it's not needed if the centrifugal clutch is working properly,


    No you can't take the clutch lever off the bike because there is no way to disengage the centrifugal clutch once it locks up due to lack of lubrication between the crankshaft extension sleeve and the clutch bell, otherwise known as a clutch drum.

    For this reason the centrifugal clutch needs to be be modified; allowing lubrication in between the crankshaft extension sleeve and the clutch bell.
    Some people make comment that their centrifugal clutch never needs lubrication but that's only because their engine has leaky crankshaft seals, allowing 2-stroke oil to blow by and lubricate the crankshaft extension, which is not how the crankshaft seals should work, for numerous reasons.

    If the crankshaft seals are in good condition, you can expect the centrifugal clutch to lock up within 300 kilometers (185 miles) due to lack of lubrication.
    A modified centrifugal clutch will last forever if lubricated every 100 kilometers (60 miles).
    Jonathan Silva likes this.