biggest motor/ hp with shift kit?

Discussion in 'Motorized Bicycle General Discussion' started by carcrafter22, Feb 17, 2013.

  1. carcrafter22

    carcrafter22 New Member

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    I am planning on another bike build after completing my Felt/99cc build (which is working out wonderfully and a joy to drive).

    I have thought of building a bike with a shift kit so I only have to run 1 chain to the rear wheel for a nice clean look. I'd like to run a 4 stroke engine and build my own shift kit setup.

    My main concern will be the strength of the chain that would run from the crank to the rear wheel, will it stand up to a 3-4hp engine?

    Should I build my own crank gear set and run a #41 chain to the back?

    The only shift kit setups I've seen so far are with small 49c engines and the like usually not producing much power (instead taking advantage of the added ratios).

    Currently I have my Felt bike with a 99cc predator and 10:1 ratio that works fine for me, pulls any hill in the area with ease, this is the only thing I really have to compare to.


    So will a standard bike chain work or will it break with 3-4hp? Whats the recommended limit for standard bike chain?

    Thanks
    Randy
     
  2. young grease monkey

    young grease monkey New Member

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    i would do a single speed and a large rear sprocket to minimize the load on the bearings, and single speed would allow you to use thicker chain. forget putting 4hp through bicycle chain and sprockets if multiple speeds is what you want from it. maybe cvt to jackshaft?
     
  3. The_Aleman

    The_Aleman New Member

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    What you mean by "standard" bike chain can vary depending on the type of bicycle and drivetrain it has.

    Bicycles with derailleurs almost always use narrower chain than bicycles with internally geared hubs.
    Also, bicycles with derailleurs have variable chain angles - the chain will not be straight in certain gears, which can pose a problem during high load.

    All that said, a bicycle chain with good alignment shouldn't have a problem with a Pred 99.
    If you're going to use an IGH, I'd worry more about whether that hub can take the power than if the chain can handle it.
    You can easily run a heavy chain like 415H or 41 with an IGH.
     
  4. racie35

    racie35 Active Member

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    have you considered belt drive like a whizzer has?
     
  5. carcrafter22

    carcrafter22 New Member

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    This is what I was suspecting.

    I think the internal geared hub is out, in my research all that I've seen try it have had them fail so thats a no go.

    More than likely I'll go ahead and install my variable pitch pulley on my felt and see how I like it, if it works like I think it will then I'll just run the same variable pulley/ belt setup on the next bike as well since I like it so much already.
     
  6. young grease monkey

    young grease monkey New Member

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    you can get a pulley from McMaster-Carr that changes pitch if you tighten the belt; its like a cvt but you control the ratio with a belt tensioner clutch. i plan on doing this once i finish my build 'cuz they cost over $100.
     
  7. carcrafter22

    carcrafter22 New Member

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    I have one already, cost me $68 from mcmaster carr.
     

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