I need to get a motor from an electric motorbike to drive a single-speed BMX Bike chain, and I haven't worked with bikes/sprockets before so I don't know where to start (I was only supposed to be doing the throttle and electronics, not sure how I ended up with the chain drive).
I know I need a sprocket with as few teeth as possible (~10-14 or less) and can be mounted onto a 9.5mm shaft double flattened to 8.4mm, and 4.5mm long, and have the teeth fit a standard single-speed BMX bike chain.(measurements are from a set of calipers, motor doesn't have any specs :P) I have a sprocket from the motor, but it isn't the correct tooth size/spacing for a bike chain.
Is this something that exists or can be made on a part-by-part basis, or do I need to weld something up?