A little help

Discussion in 'Motorized Bicycle General Discussion' started by Motor awesomeness, Nov 3, 2014.

  1. Motor awesomeness

    Motor awesomeness New Member

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    I have a mountain bike with a broken chain tensioner and I want to convert it to a motorized bicycle. My plan is to make it FWD because of the chain tensioner is broken. I have plans drawn up and I want to know if this will work. If something isn't right on the drawing, give me a suggestion and I'll modify it. Note I want to do this conversion with very little money as possible.
     

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  2. crassius

    crassius Active Member

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    something like that could be done - don't forget room for a gas tank & keeping exhaust off your knees

    I'd certainly want a clutch tho just to help prevent headstands if the motor stalls or seizes at 30mph.

    You might also want to look at pics in which folks have mounted motor behind the seat.
     
  3. maniac57

    maniac57 Old, Fat, and still faster than you

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    I built one with a rack mount chinadoll on a full suspension mountainbike which could just as easily have been installed on the front wheel with a few mods. The ragjoint sprocket does not care which wheel it is on. My setup DID require welding though.
    It ran like a champ and was very comfortable!
    Here's a link to the build thread:
    http://motorbicycling.com/showthread.php?t=53935
     
  4. BobbyT

    BobbyT Member

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    I suggest you not to mount a chain drive to a front wheel. To Dagerous!.duh.
     
  5. Dan

    Dan Staff
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    Just curious Bobby. Why would it be more dangerous then a conventual mounting?

    A member here had a front wheel that he didn't like because it was "squarely" I've never built one and am just wondering.
     
  6. Motor awesomeness

    Motor awesomeness New Member

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    Thanks for all the replies, I will use the stock gas tank that came with the engine and I'll point the exhaust end away. I might want to ride my bike to school so the exhaust has to be clean with minimal to no smoke. And I'll be sure to keep the oil:gas ratio above 40:1 as most chainsaws require. And plus I'm gonna use the original bike chain that came with the bike so all I need is 2 bicycle sprockets, I just need a small one for the engine and a big one on a tire. I'm still open for more suggestions.
     
    #6 Motor awesomeness, Nov 3, 2014
    Last edited: Nov 3, 2014
  7. BobbyT

    BobbyT Member

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    If the chain came off it could cause a endo.... On the rear its bad enough if the wheel skids but more controllable then the front.
     
  8. crassius

    crassius Active Member

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    just remember the gas tank has to be higher than the motor
     
  9. FFV8

    FFV8 New Member

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    Easy enough to do:

    http://motorbicycling.com/showthread.php?t=57161

    Handles just fine.

    Chain drive on the front is safe, as long as things are well built.

    Gas tank is behind the seat, works great.

    You really want a clutch, and good brakes.
     
  10. Dan

    Dan Staff
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    Great safety tips!

    ===================

    That is cool, FFV. Purty work.
     
  11. Motor awesomeness

    Motor awesomeness New Member

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    True the gas tank has to be higher than the motor, but I want to use the original tank cause I want this project to be as cheap as possible. Plus the chain shouldn't come off if i keep it tight. I think in the first post I said no welding because it's not that i don't have have welder, I have a welder, but I live in a apartment complex and their isn't a outlet on the outside of the building so the only way I could weld is to take out the generator which is very heavy. When I'm done, I have to walk down a flight of stairs to the storage lockers with the welder and the generator which is heavy and requires 2 people and I don't have another person to work with me. That's why I said no welding.
     
  12. Dan

    Dan Staff
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  13. Motor awesomeness

    Motor awesomeness New Member

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    Like I said, I will use a chainsaw engine and the original tank. I'm not gonna use a external tank. I might make just use a metal container if I do decide to use a external gas tank. Won't be EPA approved, but it's functional.
     
  14. FFV8

    FFV8 New Member

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    Cheap as possible? - well, that depends on how good you are at scrounging. I have about 175 bucks in parts on my 29'er. New engine, new sprocket, new chain, new 203mm rotor..


    No welding?
    Possible. But it will look like a frankenstein erector set job, and it will be a lot harder to build. Perhaps you could make friends with a neighbor? Or fab the parts & weld everything at the storage locker with the genset & welding machine?

    Any FWD bike needs to be a solid build, because it can really hurt you if it fails. A life altering injury - check out what happened to Bairdco when he had a front end failure. It ended his career, put him out of commission for months:

    http://motorbicycling.com/showthread.php?t=45937

    B
     
  15. crassius

    crassius Active Member

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    That tank looks a bit low - is the carb really gravity fed?
     
  16. Dan

    Dan Staff
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    My bad. was juggling 3 threads and confused yours with another.
     
  17. FFV8

    FFV8 New Member

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    Gravity? Nope. That engine will run with the front wheel 4 feet off the ground.

    Standard carb for that engine includes a fuel pump. Second line is return fuel to the tank from the engine. Primer pump on the bottom of the carb.

    B
     
  18. Motor awesomeness

    Motor awesomeness New Member

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    Guys the carburetor is gravity fed and i can adjust the carb as needed. And in response to FFV8: the storage lockers are in the basement of the complex. It's very dusty there and other peoples stuff are there too. So doing what you said, it would be a fire hazard and possible damage to other property.
     
  19. FFV8

    FFV8 New Member

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    I have never seen a chainsaw with a gravity feed carb. please post some pics.

    Sounds like you need to find a place to do the work before you tackle a project like this.
     
  20. Motor awesomeness

    Motor awesomeness New Member

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    Just saying, I don't think it's possible to have a pump fed carb on on a chainsaw. I think their just gravity fed. And my place to work on it: outside by the bike rack.
     
    #20 Motor awesomeness, Nov 4, 2014
    Last edited: Nov 5, 2014

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