HFT 5-1/2 HP engine in a Cranbrook

Discussion in 'Frame Mounted Engines' started by Maybe, Nov 23, 2016.

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  1. Maybe

    Maybe Guest

    I am toying with the idea of sticking a HFT 5-1/2 HP engine in a Cranbrook with a 3-speed rear wheel overlaid with a peddle sprocket. It would be fed by a simple jackshaft belt-driven with a centrifugal clutch. The final drive would be #41 roller chain. A rim caliper rear brake .
    Alternatively I could use a 4 HP Lawnboy 2 stroke if the HFT won't leave peddle sprocket room. I dug ot an ancient Bultaco Metralla fuel tank that I need to evaluate for rust damage. Both engines are recoil rope starting.
    Just thinkin'

  2. darwin

    darwin Well-Known Member

    Lotta ponies for a stock Cranbrook drive train, I don't see it holding up without upgrades to the wheels, chain, bearings, 3sp hub etc.................bicycles are designed for 1/3rd hp humans and that is the fittest humans. Then figure in the elcheapo factor you get the idea.
    Timbone likes this.
  3. wheelbender6

    wheelbender6 Well-Known Member

    The Cranny is plenty sturdy for 50cc engines. For a 5 horse motor, I would look for a used pre-2000 beach cruiser. They are heavier but durable as a tractor.
  4. KCvale

    KCvale Motorized Bicycle Vendor

    You don't want to start with a small Toy bike.
    The 29" Micargi Fatal Love has enough frame strength and room to squeeze an 88cc 4-stroke in it.



    Then the hard part starts, making everything custom down to how the throttle hooks up.
    Just letting you know what you are in for, you will need machine shop tools and skills.
  5. Sgt. Howard

    Sgt. Howard Member

    The Crannie might handle the horse power, but the stock drive train and hub won't. Use a conventional drive for power.
  6. Frankenstein

    Frankenstein Well-Known Member

    Well at least you dug up something less than a year old..
    Timbone likes this.
  7. KCvale

    KCvale Motorized Bicycle Vendor

    I like digging up old topics too ;-}