Centrifugal One can pedal start with centrifugal clutch, true or false?

Discussion in 'Transmission / Drivetrain' started by iron_monkey, Dec 25, 2008.

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  1. iron_monkey

    iron_monkey Guest

    Two people have claimed this is possible for the happytime kits (may not be true for other kits):

    A couple of kit vendors/factories also claim to sell dual (pedal/pull)start engines.

    True or false, and if true how is it possible that the clutch can also allow coasting down hills? (or it doesnt?)

  2. bluegoatwoods

    bluegoatwoods Well-Known Member

    Well, I woulda thought that it was impossible. But someone will come along with better info than I have.

    I'm wondering how an add-on centrifugal clutch can fit it and how it can work. Maybe things will become clear with a few more answers to your question. Good luck.
  3. srdavo

    srdavo Active Member

    I have seen these kits online & read about them, but have no hands on experience with them.

    I have ridden a couple of NE5 whizzers, with the auto-clutch...and they CAN only be pedal started. I believe it's a one-way bearing, as quadmaniac stated.
  4. arceeguy

    arceeguy Active Member

    Well, the answer is that some can and some can't.

    I purchased a centrifugal clutch kit and pull start from Boygofast, along with an engine kit. I had assumed that I would need the recoil start because I would lose the ability to pedal start it. Turns out the centrifugal clutch assembly has a one way bearing in it to allow you to pedal start the engine. Even with the centrifugal clutch, you still need the manual clutch lever if you want the ability to pedal without the engine.

    Apparently some of the GGG (Give Gas and Go) kits do not have this one way bearing, and they need the recoil start.
  5. iron_monkey

    iron_monkey Guest

    so with this one way bearing the wheels will still transmit drive to the engine while coasting (unless manual clutch is disengaged)?
  6. arceeguy

    arceeguy Active Member

  7. iron_monkey

    iron_monkey Guest

    i still dont get how this works.

    If the freewheel bearing allows the engine to transfer torque to the wheels, then the wheels cant do the same to the engine; then it cant be pedal started. Just like on a pushbike the wheels cant turn your pedals when you have stopped pedaling but the bike is still moving.

    If the freewheel bearing allows the wheels to transfer torque to the engine so it can be pedal started, then the engine cant drive the wheels by definition.

    The only scheme i can think of that allows pedal starting an automatic is the use of two centrifugal clutches. One that turns the wheels when engine reaches certain rpm, and another one that turns the crankshaft when the wheels reach a certain rpm.

    edit: Ah I get it now. The freewheel bearing allows the wheels to transfer torque to the engine so it can be pedal started, then the engine cant drive the wheels. But while the engine cant drive the wheels via the freewheel, it can still drive the wheels by connecting it to a centrifugal clutch that has a parallel connection to the wheels. Cant believe it took me this long to wrap my head around this.
    Last edited by a moderator: Dec 27, 2008
  8. srdavo

    srdavo Active Member

    clutch roller bearing

    the only reason I know anything at all about these clutch roller bearings is, I had one fail, on my Currie Ebike.
    this type of bearing, (for my use) allows the motor sprocket to freewheel, while I operate in 'pedal only' mode.
    to make a long story, longer..... on my currie kit.....when my bearing failed, while I pedaled without the engine, I experienced a bunch of drag.
    I assumed the motor was failing, so I bought an aftermarket replacement motor.
    this did not solve my problem....still had drag. this was my cure.

    these bearings are used in many things.(from what I've read this morning)..fishing reels....copy machines....& ... some motorcycle starters. (gotta love google)

    except for this explanation.....
    more info

    for a better look, check out this pdf file

    :banghead: I wish I'd read your edit 1st!!! oh well, I wanted to know more about it anyway.
    Last edited: Dec 27, 2008
  9. arceeguy

    arceeguy Active Member

    Don't forget Nordic Track exercise machines and automatic transmissions! (in an automatic tranny, it's called a sprag clutch)

    There are two speed automatic jackshaft kits that utilize these freewheel bearings. (a two speed auto motorized bike.... hmmmm.......)
  10. srdavo

    srdavo Active Member

    I've seen those 2 speed jackshafts.....if I remember right, they are dirt cheap.
  11. Skyliner70cc

    Skyliner70cc Active Member

    Anybody know if a SBP shifter kit can be installed on one of these engines with the centrifugal clutch? Anybody got pics of the right side of the engine?

  12. just for the record i had a peugeot moped with a centrifugal clutch that i could pedal start with no problem.