Help with sprocket instructions

Discussion in 'Frame Mounted Engines' started by onij, Jul 30, 2008.

  1. onij

    onij New Member

    Sorry for the double post, wasn't sure where this belonged.
    Alright, so I've had my motor bike kit for over a month now, and I've been too scared to start on it cause I'm afraid I'm gonna break something. Anyways I'm ready to start trying but I've run into a problem. In the instructions I received, I'm pretty sure that it says I may need to enlarge the hole around the sprocket so it will fit around my rear wheel bearing housing, and touch the spokes. Am I understanding this correctly?

    Can the sprocket just fit around the end of the circular housing, or does it actually need to be up right next to the spokes. Please help!

  2. pedalpower

    pedalpower Member

    I'm a noob, but I just installed my engine, sprocket and chain. the main problem with not having the sprocket up against the spokes is that the chainline will be off-that's my first thought, every setup is unique. the sprocket really just needs to clamp up against the rubber washer thingy. I don't think doubling or tripling those things would work just because of the added lateral torque on the sprocket/spokes. If you are really attached to the wheel there is a machined sprocket clamp on ebay. livefastmotors or boygo fast of someone. good luck.
  3. spad4me

    spad4me Member

    Dry fit every thing first, without tightening the bolts.

    Do you have a coaster brake on your bike?
    This is usually the thing that requires a larger hole in the sprocket.

    Test fit every thing .
    Install the sprocket on the backwheel.
    Or install the engine first.
    Then the chain.
    Do you feel comfortable with the fit and placement of the parts.
    Go ahead and install the stuff, tighten and align the parts.
  4. pilotpeat

    pilotpeat Member

    Usually with the kit you will get two rubber rings with bolt holes in them and two pieces of metal that when put together make a circle the same size as the rubber "donuts". One of the rubber donuts gets slit between a pair of bolt holes. The rubber with the slit will go inside the wheel between the spokes and the metal pieces. The other donut goes on the outside of the spokes between the outside of the spokes and the sprocket. So when you are all done you have sproket, donut #1, spokes, donut #2, metal things.

    you don't always have to ream out the center hole of the sprocket-most of the time it will fit. Make sure you have the rubber donut under it when you try and it might just work perfect. If it is tight on the wheel it helps center it better.

    hope this helps.

  5. HoughMade

    HoughMade Guest

    As an aside- I don't understand why people are saying that the hole on a coaster brake bike needs to be enlarged- Ive done 2 and all I've ever needed to do was grind the rim off the dust cover. Enlarge the hole with a dremel and you risk getting it off center and the hole locates the sprocket. It is a close fit, but it fits.
    Last edited by a moderator: Aug 1, 2008
  6. BoltsMissing

    BoltsMissing Active Member

    Depends what sprocket is in the kit. I found there are 2 differant size centre holes.
    The sprocket that is straight is the smaller sized hole than the sprocket that has that rim/concave type thing around it. ( see pic)

    Pics. would help us see what ya got, including the rear wheel to see it's condition

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