Use current bicycle gears??

Discussion in 'Motorized Bicycle General Discussion' started by cschade, Aug 8, 2014.

  1. cschade

    cschade Member

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    Hello, I'm thinking about building a motorized bike using a Harbor Freight 3hp engine. Two questions -- first, on the Harbor Freight website it says the shaft rotates counter clockwise. Is this counter clockwise as viewed from the visible end of the shaft? Also, I'm thinking about using the pedals of the bike as a jackshaft. For instance, mount the engine so the engine shaft is sticking out the left side of the bike as viewed from the seat. Then, run a chain from the clutch to a sprocket mounted on the left side of the pedal crankshaft, opposite of where the sprocket is normally mounted. Then, let the engine turn the bikes gears. I've attached a sketch. Can this be done. I'd have to cut off the pedals and mount foot pegs somewhere else. Thoughts?

    .scratg.
     
  2. The_Aleman

    The_Aleman New Member

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    Counter-clockwise is while facing the end of the shaft, yes.
     
  3. crassius

    crassius Well-Known Member

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    knew a guy just turned his pedal crank around to sit on left & reversed rear wheel and freewheel action
     
  4. 2door

    2door Moderator
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    Check your local laws before removing the pedals. Some jurisdictions require them or they will call your bike a motorcycle and will require motorcycle registration, insurance, etc.

    Do some reading here on the Harbor Freight engine conversions. Use the search feature or check the DIY section for non-kit engine installations. I feel you have a lot to learn before attempting this installation. Good luck.

    Tom
     
  5. cschade

    cschade Member

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    Please, more info!
     
  6. cschade

    cschade Member

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    Thank you, and you are right -- I have a lot to learn! The only motorized bike I've built before was friction drive, so I'm not used to chains and sprockets :).bf.
     
  7. cschade

    cschade Member

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    Another question -- how many teeth should the sprocket be (with the chain running from the engine to the jackshaft). There are some pretty big hills around where I live, but I'm only 130 lbs. 30 tooth, 40 tooth, 60 tooth?
     
  8. crassius

    crassius Well-Known Member

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    he just turned stuff around, I believe the only thing he bought was the freewheel that ran in the other direction
     
  9. cschade

    cschade Member

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    Thanks! Do you know where he got the freewheel from, or it is possible to change the direction of the freewheeling?
     
  10. crassius

    crassius Well-Known Member

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    not sure if he turned the pawls around on it or it came that way, but I seem to recall it was threaded backwards too

    this was maybe a year & 1/2 ago

    you should try googling

    he had a progressive drive on a 4-stroke that was a lot easier if it came out on the right side
     
  11. BarelyAWake

    BarelyAWake New Member

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    I'm not recommending these outlets, dunno beans about 'em other'n they had the handy info to link - as always, shop around ;)

    & if you'd like a reversed freewheel w/that;

    http://www.treefortbikes.com/product/333222380078/945/ACS-SouthPaw-Freewheel-1-and-8.html
     
  12. cschade

    cschade Member

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    Thank you for your help, everybody. I've been doing a lot of reading up on the subject, as someone suggested. Another question I have is: how would I go about mounting the larger sprocket on the cranks? And, what size sprocket would you recommend? I'm leaning toward a 50 tooth with a 12 tooth on the clutch, because I have a lot of hills where I live. What are your thoughts?
     

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