CVT with large sprocket????

Discussion in 'Motorized Bicycle General Discussion' started by capturedbyrobots, Jan 20, 2009.

  1. capturedbyrobots

    capturedbyrobots New Member

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    So I saw this CVT video on Youtube,
    and the guy has a really large sprocket on the motored side,
    looks to be attached to a disk mount.

    YouTube - MoToRiZeD BiCyCLe - CVT+HoNDa GX35


    My question is this.
    Where in the world can I find a sprocket this big,
    and what kind of chain do you think they are running?
    Anybody know what they got this sprocket off of?

    I figure with a sprocket that large,
    a jackshaft won't be needed using a Pocketbike CVT on a motorized bicycle.

    Goped sprockets with tiny #25H chain goes up to a 98 tooth.
    Can anyone help with this?
    I'm tired of my scrubber drive on my bike and not being able to climb big hills
    like I can do easily with my CVT gopeds.
    I live in a very hilly area, so I need to find this.

    Thanks!!!!



    Oh, and here's my CVT goped.
    [​IMG]
     
    #1 capturedbyrobots, Jan 20, 2009
    Last edited: Jan 20, 2009
  2. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    You can just cut the front off of one of those, turn it around backwards and set it up so the rear wheel rests on the rear wheel of the bicycle....

    BOOM! Instant motorized bike.
     
  3. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    You can just cut the front off of one of those, turn it around backwards and set it up so the rear wheel rests on the rear wheel of the bicycle....

    BOOM! Instant motorized bike.
     
  4. Dan

    Dan Staff
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    Howdy Capt.
    Andy makes custom sprockets. Upper left. I watched that vid 3 times. Is to small to be a belt and sounds like a chain. Getting a CVT to work is one of the last "holy grails" I can think of with motorized bicycle riding. For a 35cc, he seems to have it!

    Would love to know the numbers. (T count, CVT size and ratio)
     
    #4 Dan, Jan 20, 2009
    Last edited: Jan 20, 2009
  5. capturedbyrobots

    capturedbyrobots New Member

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    Yep, gotta get a bigun sprocket,
    and then I'll be set.
    I'll PM andy.

    This guy sure seemed to get it right.
    It is definitely a chain drive. I emailed him,
    but have not received a response.

    Oh, and I already use the back end off a spindle drive Boxer ped for my MB now
    (made by Dean at Pipelyne....)
    Here it is...
    [​IMG]
     
    #5 capturedbyrobots, Jan 20, 2009
    Last edited: Jan 20, 2009
  6. Creative Engineering

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    Guys,

    Give me the tooth count and the chain size and I can make them in batches of 25 for $40.00 each.

    Jim
     
  7. Large Filipino

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    In the spirit of sharing what I know,if you get a jackshaft in the mix you may not need such a large wheel sprocket. In fact an average 44 tooth spoke sprocket standard on 2 stroke kits would work well on a 26 inch wheel.

    For example,looking at my buggy bike in the pictures forum notice how my 3 speed hub is a tiny 19 tooth sprocket. It goes to a 10 tooth sprocket on the jackshaft. But on the other end is a 20 tooth sprocket. I just made that jackshaft a 2 to 1 reduction. Then my Titan gearbox is a 5 to 1 ratio. That's 10 to 1 total. 2nd gear is a fixed gear on my hub and it pulls quite well in that gear. 1st is just a hill climber so this jackshaft allowed me to link up a 19 tooth to a 20 inch wheel.
    So now you got your CVT that I've been looking at for quite a while actually I see clearly now how it mounts up. It's a 7 to 1 ratio at it's lowest excellent hill climbing then a 1 to 1 at it's fastest. A 44 tooth to a 26 inch wheel can get you started in low but you'll have no hill climbing at all and ridiculous top speed if your engine can take it I doubt it would have enough power actually for gearing that high. But let's get a jackshaft in there 20 tooth engine drive to 10 tooth to the wheel. Suddenly your gearing gets cut in HALF and that 44 tooth sprocket would be the same as an 88 tooth sprocket without a jackshaft!
    It's possible,man. If I had the funds it would have been my reality already. Imagine my trike with the three gears currently AND a CVT. That would be like tractor trailer gearing how sick would that be?

    (edit) OMG that CVT is reverse rotation. If I had that it would take absolutely nothing much to adapt to my trike. I'm right about this right?
     
    #7 Large Filipino, Jan 21, 2009
    Last edited: Jan 21, 2009
  8. capturedbyrobots

    capturedbyrobots New Member

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    I just wanted to keep it simple....
    I'm not experienced with Jackshafts at all.
    The CVT adds enough stuff to worry about.
    I can spend $30 or $40 on a sprocket and be done.

    Oh, and all PB CVTs reverse rotation.
    They have a gear box (3.75 to 1) before the output.

    Keep in mind, the CVT will allow you to pull the max gearing
    for top speed you're used to, but will add a TON of low end to it.
    You take off like a rocket, as long as the Variator is tuned right.
     
    #8 capturedbyrobots, Jan 21, 2009
    Last edited: Jan 21, 2009
  9. Large Filipino

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  10. Dan

    Dan Staff
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    You have my mind going LF. With a conventual chain drive, it would need to be around 18 to 1 so as not to smoke the clutch. So coming off a 3 to 1 CVT at 3,600 rpm maybe a gear box for further reduction? Been on this for 3 days and still going. Did play with the thought of a just larger CVT or dueling CVTs. dunno, but this is a great thought. Maybe a small gear box..... Hmmm
     
  11. spad4me

    spad4me New Member

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    The sprocket from andy is the right way to go.
    You will need to make a custom drive sprocket. I use the thin (.81 thickness) sprocket from thats dax.
    Grind down the old cvt sprocket keeping the shaft and splines only, and weld it to the thats dax sprocket.

    The titan drive sprocket may work it looks close.
     

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