125cc Bicycle engine help?

Discussion in 'General Questions' started by agrmodz, Jul 11, 2016.

  1. agrmodz

    agrmodz Member

    I'm thinking of putting together a 125cc motorised bike together, i'm just trying to figure out what frame would house the massive 125cc engine best and what motor would be the easiest to mount? also 2 stroke or 4 stroke?
    What would i have to change on the engine to make it mountable?
    If someone could sell me one already put together that would be amazing!
    Thanks!
     

  2. Jonj57

    Jonj57 Member

    While my own experience is limited 125cc and bike frames might not go well together and could be dangerous without dropping a lot of work and money into them and the setup. Bikes weren't mean to go that much faster than 30/40 or deal with that kind of torque. My advice is to start small and then see if that's still the kind of thing you're after once you know you need it.
     
  3. Frankfort MB's

    Frankfort MB's Well-Known Member

    Guess it's a good thing I'm putting a 9hp 212cc on a 60 year old bike frame;):p
     
  4. agrmodz

    agrmodz Member

    Yeah, i've built loads of 49-80cc motorised bikes,i want to try something a little different, i'm just trying to figure out the perfect frame and stuff.. obviously the bike is going to have to have heaps of upgrades so it doesn't fall apart.....

    Woah, send me pictures when your done!!!
     
  5. jaguar

    jaguar Well-Known Member

    it will never happen.
    motorcycle engines are too heavy and too wide for a bicycle frame.
     
  6. Frankfort MB's

    Frankfort MB's Well-Known Member

    I'll make it work. Probably will get hurt but all for the fun.
     
  7. Frankfort MB's

    Frankfort MB's Well-Known Member

    And it's not a motorcycle engine, it's a harbor freight;)
     
  8. Frankenstein

    Frankenstein Active Member

    At least the frames from 1950 were built to be thrown off a building into a subway system to be run over by a dozen trains and still be usable... I'd like to see pictures when it's finished that's too damn cool. Need a test pilot?
     
  9. Frankenstein

    Frankenstein Active Member

    I got mah gerd helmet on ahuck
     
  10. darkfighter

    darkfighter New Member

    I have a harbor freight 6..5 hp that I originally planned to use in a go-kart. The thing would be simple too wide at 14 inches to be used in a standard bike frame, although the torque and reliability is great.
     
  11. Frankenstein

    Frankenstein Active Member

    What about 2 standard bike frames welded together?
     
  12. Frankfort MB's

    Frankfort MB's Well-Known Member

    What about a regular bicycle w/o pedals????
     
  13. Frankfort MB's

    Frankfort MB's Well-Known Member

    This will be the poor soul who donated his life to science and technology:)
     

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  14. Frankenstein

    Frankenstein Active Member

    What about a regular pedal without a bicycle?! And motorized!
     
  15. Frankenstein

    Frankenstein Active Member

    Haha that poor soul gonna get possessed by a speed demon. So I still got my good helmet on when you need a second soul donation to operate the first one.
     
  16. Frankenstein

    Frankenstein Active Member

    Speaking of which, just finished replacing the motor in my bike tonight, and boy does this one have a hell of a kick to it, I'm through my entire range of gears and still accelerating before I get through 1 and a half blocks. I'm probably going to have to install a smaller gear on my nuvinci, there's too much power left over that needs releasing in the form of top speed.
     
  17. Wolfshoes

    Wolfshoes Member

    From memory I seem to remember Whizzer four strokes that have been around since the 1930-40's are 138cc's. The question is what is the dimensions and weight of synchromesh motor driven cycle engines and what about them prohibits use on a bicycle. Since the drive sprocket is set further out from the center of the frame, a fat tire bike would likely be needed. Only one style of fat tire bike rims appears to be on the market and it has thin spokes and not enough of them for the common attachment techniques of the rear sprocket. Not to mention brake problems. Installing a motor driven cycle engine on a bike would, perhaps legally in my area, allow it to rumble down the road like a Harley at 30 mph instead of screaming at you at 25 mph like a China Girl. I would expect it to be more frequently attempted in the future.
     
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