Hi from New Zealand


New Member
Feb 9, 2009
New Zealand

just popped in here to ask for some advice on a "project" I'm building. I guess technically it's not a bike (see pic) but it had its beginnings as a bike.

My intention is to motorise it with a 70cc 2 stroke chainsaw engine.

I intend running a 12 - 15 tooth sprocket on the engine and 70 - 80 on the axle of a 20 inch tyre.

My concern is that using this set up will give me a drive ratio of around 6:1 which calculates out to a top speed of about 95km/h at 6000, which is not even top rev's for the engine.

Do you think this set up will work or am I dreaming??

Thanks in advance for your help.


Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
up north now
I would go with more reduction....other than that, go for it!

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