gearing for kit on moped frame

katch26 · Oct 1, 2012

so my employee's been building this frankenstein bike for quite some time and it looks like we'll have it running in the next week or so. I have some reservations on the gearing but it's hard to figure out ( with no motorized bicycle kit) experience. The bike is built on an AMF roadmaster frame with tomos 16" rims. I found a calculator, see attached, and it looks like it might work with the current gearing. So my question is, on a completely stock kit, will it have the guts to pull the gearing?
thanks.

JonnyR · Oct 1, 2012

what engine is he using and is that a ratio for a jack shaft?

katch26 · Oct 1, 2012

It's the 66cc kit from boygoesfast. The 10:22 is just front and rear sprockets no jack shaft kit or anything.

bigbutterbean · Oct 2, 2012

you have to count the teeth on the gears on the clutch side, I think its 22 and 80, but I could be wrong. you have to add those gears to properly calculate the ratio though.

katch26 · Oct 2, 2012

Oh ok I got those numbers from this thread
http://motorbicycling.com/showthread.php?t=41826.

Also I included those numbers in the pic I attached

bigbutterbean · Oct 2, 2012

I had it almost right, but a little backwards, lol. I said 22 and 80, its actually 20 and 82.

katch26 · Oct 2, 2012

good enough for government work right? so what do you think, should it run ok?

MotorBicycleRacing · Oct 2, 2012

katch26 said:
good enough for government work right? so what do you think, should it run ok?

The redline on the 66 cc motor is about 7000 rpm so that
will change your gearing a bit from your 6000 rpm

katch26 said:
so my employee's been building this frankenstein bike

Pics please!

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gearing for kit on moped frame

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