Need Advise

Discussion in 'Bicycle Repair' started by Michigan motorist, Jul 19, 2016.

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  1. Hi everyone I just received a EL cheapo roadmaster mountain bike with three front speeds and 7 rear speeds. I would like to mount a 3hp flat head Briggs engine on her above the rear wheel (won't fit in the frame) I'm going from a #35 chain 11 tooth centrifugal clutch to a 32 tooth on a jackshaft from there I want to have a 11 tooth #415 sprocket to my hub adapter one from MM. A few questions is the wheel sturdy enough for the torque (14g)? And I'm having problems finding some gears websites? And you might ask how the engine will be mounted? well I'm making a bracket that will weld onto the steel frame. Thank you anything will belp.

  2. Frankfort MB's

    Frankfort MB's Well-Known Member

    Sounds pretty neat but you would probably need a stronger back wheel to be able to handle the extra weight and torque.
    11-13 gauge is the best for motor bikes but you also need a really good hub for it too, I've had good luck out of cheapo free wheels. My only problem was finding a rim that wouldn't warp with heat from the brakes

    I'm not saying it couldn't be done with what you have I'm just not too experienced with that motor so idk it's power. If it's about like a HT then it will be fine.
  3. CrazyDan

    CrazyDan Active Member