My first motorized bike build-four stroke honda

Discussion in 'Motorized Bicycle Welding, Fabrication and Paintin' started by cooperDG123, Sep 12, 2015.

  1. cooperDG123

    cooperDG123 New Member

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    I believe I have found a solution to my shifting problem, it's not ideal but I think it will work. The top lever will shift up and the lower lever will downshift. Shouldn't be to hard to rig up with just brake cable. Switching steen levers isn't as hard as I thought it would be. The only possible problem I see is not having enough travel or pulling power with the cables. Brakes will be on the throttle side, one lever will actuate Both front a back brakes.
     

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  2. cooperDG123

    cooperDG123 New Member

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    Started work on the jack shaft after school yesterday. I'm getting pretty close!!
     

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  3. cooperDG123

    cooperDG123 New Member

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    Jack shaft is 100% complete. Next is chain tensioners any one know of a good place to start for that? Skateboard wheel? Spring loaded?
     

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  4. MotorBicycleRacing

    MotorBicycleRacing Active Member

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    You do not have to be an adult to race with Socal Motor Bicycle Racing.

    Your parent or guardian needs to sign the race waiver.
    You must wear all the required safety gear.
    That's it...our youngest racer is 8 and there are quite a few racers
    that are under 18 years old.

    Will get you all the info about the Oct 17th race soon.
    thanks.
     
  5. KCvale

    KCvale Active Member

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    Correct, that is the problem with trying to shift with a handlebar lever.
    Not near enough travel or hand strength to move that shift mech like it is for say a 3-speed internal bike hub.

    You could fashion a long shift arm to the shifter output and have plenty of mechanical advantage to shift with a really long push / pull lever sort of like Rat Rod comics used.

    [​IMG]

    [​IMG]

    [​IMG]

    Then again if you have some seriously long strong arms you can just reach down...

    [​IMG]

    Hehehe, I love those old comics.
     
  6. cooperDG123

    cooperDG123 New Member

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    yep...its starting to sound like a suicide shifter is my only option. Those comics are nuts!
     
  7. KCvale

    KCvale Active Member

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    Heheh, ya, I grew up with Rat Rod posters and toys.

    It is not your only option, you can fashion an electric solenoid system to move the shifter but far from cheap.
     
  8. cooperDG123

    cooperDG123 New Member

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    Sounds Like an idea for gen 2. Hopefully after i finish this build I'll start another with similar design with a bunch of improvements.
     
  9. cooperDG123

    cooperDG123 New Member

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    I went for a test run today (If you can call it that) and immediately stripped the fixed gear side of my hub, this is the side the engine drives. My drive sprocket on the wheel uses the threads from a fixed drive sprocket. The locking ring that goes on after the sprocket completely stripped the hub threads. I'm not sure what to do now. Maybe a 29er hub with a sprocket hub adapter? Would this work? I don't think the aluminum hub threads can hold up to the tourqe of the engine.
     
  10. KCvale

    KCvale Active Member

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    Well, I suggest you look at how MotoPed builds their drive trains.
    The whole frame for that matter if you want to play with big engines.

    [​IMG]

    [​IMG]

    [​IMG]

    That is just an 88cc 3-speed 4-stroke but the frame will take much larger engines as will the drive train as it is essentially a nice full suspension dirt bike... with pedals.

    $2K for the rolling frame.

    I finally sold that thing.
     
  11. BarelyAWake

    BarelyAWake New Member

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    Any disc brake hub w/your main drive sprocket drilled & bolted to the rotor mounts outa work;

    [​IMG]

    http://www.amazon.com/Quando-Orbea-6-Bolt-135mm-Shimano/dp/B00Y1N1Q1O/

    ...which hub depending ofc on your dropout width & spoke count, I linked that one only to show they needn't be costly ($17 lol) & I've used the Quando brand before, they're fine for the pennies ;)
     
  12. KCvale

    KCvale Active Member

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    I wouldn't use that hub for a rear wheel, it's a really thin axle and quick-release fastening.
    You want a fat axle with good cap nuts and use an axle stay on the drive side to keep it in place.

    Busting a sprocket mount is one thing, ripping your rear wheel out from under you riding has a considerably less friendly outcome.
     
  13. BarelyAWake

    BarelyAWake New Member

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    I think you're forgetting it's a 49cc four stroker in a road bike;

    ...one I'm quite familiar with in fact but yes, they provide solid axle disc brake hubs as well, if you're so inclined - point being the rotor mount utilized as a sprocket mount, an inexpensive, clean & simple solution ;)


    cooperDG123 - I would presume your CRF50 3sp is autoclutched, yes?
     
    #33 BarelyAWake, Sep 25, 2015
    Last edited: Sep 25, 2015
  14. cooperDG123

    cooperDG123 New Member

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    Yes it is a 3 speed auto clutch. Although it is a 4 stroke 49cc these little engines have a surprising amount of torque first gear, enough to do a standing burnout.

    I have think I have fixed my hub problem for now. The lock ring that I had on before was junk, Chinese cheese. I thought I had striped the hub but in reality it was just the lock ring. The hub threads were still in pretty good shape. After replacing the ring and plenty of locktite it seems to hold pretty well....well enough to do a burnout lol. I only was trying to test the drive train not the incomplete frame so I never went more than 10mph

    Now that my drive train seems to be solid, I can finish the frame. I still have to do the bottom frame tubes shown mocked up in the first pic.

    Does anyone know where I can get some 1" od tubing in LA?

    Anyone have any ideas for a gas tank?

    Thanks for all the help guys
     

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