Centrifugal Help ? Before I take centrifugal clutch apart.

Discussion in 'Transmission / Drivetrain' started by wan37, Apr 25, 2012.

  1. wan37

    wan37 Member

    I have a 48cc engine with a centrifugal clutch and today as I got in the driveway it went bad no pull from motor at all, still running Idles great.So I shut it down.I went to roll it in garage and it rolls with a little drag but not much with clutch lever out,or in.So were should I tear a part first.I want to see who can get my problem answer first.I'm kinda bummed,but lets have some fun guessing the problem. Thanks A bunch!

  2. Al.Fisherman

    Al.Fisherman Active Member

    First if the bike rolls with the clutch in or out, what I would check first, start with the cables, may have too much slack, then check the bucking bar and bearing, after all that then I'd adjust the clutch. Also check to make sure that you put the woodruff keys back in.
    Last edited: Apr 25, 2012
  3. wan37

    wan37 Member

    Thanks Al
    I thinking you are right about the wood ruff keys,because the centrifugal clutch does not come with notch for the key I made one it was to big so I just install it with out the key.I read in one of the forms that you may go without the key.I'm hoping that's the problem but don't know.I still don't know for sure tho.I really thought the clutch lever would work tho.So any other know any thing about this problem?I will start to tear a part tomorrow morning so give me some in put please.
  4. Al.Fisherman

    Al.Fisherman Active Member

    On these kits, I have no working knowledge of either the centrifugal clutch or the pull start, but I'm sure that they are as easy to work on as the rest of the bike.
  5. HeadSmess

    HeadSmess Well-Known Member

    you have just turned me off the centrifugal clutches on HT's fulltime :)

    you mean by "notch" that it had no keyway in its bore?

    correct terminology makes deciphering issues so much easier :)

    if it has no keyway.... *shudders*

    what are you meant to do, glue it on? omg...

    people can cut them for you but on that size bore and that width...pay up buddy!

    no keyway.. sorry. im on lunch! :jester:
  6. Al.Fisherman

    Al.Fisherman Active Member

    Working with centrifugal clutches in the past (not on a HT), they are a few ways that the clutch is held on to the shaft. Threaded on, like a automobile (not on a HT), and with a key and bolt. Other then that, I can't see how the crankshaft will turn the clutch very long before it spins on the shaft. Something has to hold the clutch on the shaft as the bolt in the end of the crankshaft won't work long or at all.

    I really can't see how this clutch will hold, if it in fact has no keyway, There might be, but I can't see one. How about a picture that we can see into the small gear.

    Attached Files:

    Last edited: Apr 26, 2012
  7. wan37

    wan37 Member

    I don't have a picture of it,but I know it really needs a wood ruff key.The gear that replaces the small bevel comes without a slot for the key.So I read on one of these forums when installed either make a slot for the key or put it on without the key.I got about 2 hundred miles on it with out it.I also know when you buy a engine with the centrifugal clutch all ready installed the key it not there too.The gear is kinda tapered so it fits on snug when press on.So vibration loses it up I think.I'm getting ready to tear in a part and check.Thanks AL and everybody else.
  8. Al.Fisherman

    Al.Fisherman Active Member

    The right way, and The Chinese way!!! I think I put a tack wield on it (as a machine shop charge would be high for these cheap engines), before I trusted it for any amount of tine. One that could be easily ground off.

    Holding a small gear in my hand, thinking about installing the stock gear in place of the non keyed clutch gear.
    Last edited: Apr 26, 2012
  9. motorpsycho

    motorpsycho Active Member

    so wait...if you run a centrifugal clutch on a h.t. engine, you still have a manual clutch lever?
    Without a woodruff key, how is the clutch drum supposed to couple wiht the shaft? seems to me that the shaft would just spin inside the clutch and the clutch would never work.
    that doesn't sound right to me.
  10. wan37

    wan37 Member

    Well the bolt that come with clutch kits from bgf is to long.The centrifugal the gear slip out a bit and it was just turning and now I think the I fixed it with a shorter bolt.The shorter bolt is hard to find but tractor supply has one.So if any one needs to know I will tell them what size to get.Plus I also added the slot and key.
    Last edited: Apr 27, 2012
  11. wan37

    wan37 Member

    Well motor the sleeve the goes over the shaft is taper then the gear locks into the sleeve with bolt.You have to make a key slot in the sleeve for a key or go with out it.I have read people going with out the key and never having problems.
  12. Al.Fisherman

    Al.Fisherman Active Member

    Are you saying... that there is a sleeve (included with kit) that goes over the crankshaft, and it is tapered on the outside, and the clutch slides over the sleeve? I still can't figure out why they didn't have a slot for a key. In post #6, what is included in the plastic bag? You can drill a hole in the sleeve, tap it and insert a allen screw through to the keyway cutaway, if you have problems.
    Last edited: Apr 27, 2012
  13. wan37

    wan37 Member

    Okay Al the sleeve is tapered on the crank shaft side,and u cut the key out on the sleeve because it doesn't have a slot.The sleeve comes out with a bolt hole at the end the gear and clutch bell slides over the sleeve and bolts down in the crank.There is a kinda lock on the sleeve the locks the gear too the sleeve.
  14. Cavi Mike

    Cavi Mike Member

    I'm confused. Is your bike manual clutch or centrifugal clutch?
  15. Al.Fisherman

    Al.Fisherman Active Member

    If they work like I think they work (see kit post #6) Remove the OEM cover plate and small gear. The manual clutch is installed on the clutch shaft, and is always engaged, install the the adapter plate supplied in kit. Install the CC, gear in CC turns large clutch gear, install the supplied cover plate.
    Last edited: Apr 27, 2012
  16. wan37

    wan37 Member

    Yes al it all fits on the small gear shaft or crank shaft and the regular clutch stay the same place.