fast motor with limited drive speed?

Discussion in 'Motorized Mountain Bikes and Road Bikes' started by steverpm, Jul 6, 2017.

  1. steverpm

    steverpm New Member

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    Hi - picked up a bike already assembled with a Skyhawk 66cc motor - runs pretty well, revs nicely with the clutch in but won't go over 20 mph or so, not even down steep hills. The low-end acceleration is fine and at any time I can pull the clutch in and high-rev the motor, but when it's engaged (even downhill) the motor will only rev to a certain speed and will actually slow the bike to around 20 mph from a much faster coasting speed.

    Seems kind of strange - I'm told these motorized bikes don't have speed limiters....

    Anyone know what could cause this?
     
  2. 5-7HEAVEN

    5-7HEAVEN Well-Known Member

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    What size are your front and rear sprockets?
     
  3. steverpm

    steverpm New Member

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    thanks for replying - the rear is 7.5 inches (roughly) with 44 teeth, at the motor the front sprocket has ten teeth, shown here - http://grubeeinc.com/Skyhawk Instructions.html (scroll down)

    I suspect both are standard with the kit - I bought the bike used and it had been sitting for a year or so...

    When I lift the rear wheel and rev the motor it all goes nice, so I can't figure out why it won't speed beyond the usual 20mph down a steep hill....
     
  4. Ryan Bouse

    Ryan Bouse New Member

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    I'm having the same issue with a stock Flying Horse from Bike Berry. Drives me crazy!
     

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