i strapped on a drill on my bike rear rack using hose clamps. i used a rear cog that i got off of an old bmx bike. i took a 3/8 inch bolt, fed on a fender washer, then the cog and then another fender washer and then a nut. although i sandwiched the cog in tight, i used a liberal amount of lock-tite on it after trying to get rid of most of the wobble. at first i tried to use a cheap dril (20 bucks/18 volt) that i got at an auto parts store. it didn't have variable speed and it performed like a 20 dollar drill should when used to power a bike - not well. i then used a ryobi 18 volt drill - it did pretty well. by running the chain to the large ring on the front cranks, i was able to get a decent amount of torque, but had to worry about my shins because the pedals would crank around and around. i will try to post some photos of it. hope you are able to build your bike/motorbike. -tmherrin

Has anyone ever seen a bicycle with a generator in the crank shaft. The generator could power the lights at night and be a self contained unit.

Your plan sounds entirely plausible but I agree that I don't think a drill motor is the best option- cordless drills are usually only a few hundred watts, which just isn't enough power to make your bike particularly fast at any gearing (your legs can probably put out over a thousand watts when pedalling hard), and corded drills will require 110 or 240V, so to power one from a battery would require an inverter, adding weight and reducing efficiency. If you are set on using your drill motor, however, your plan is valid- figure out where to attach your motor, how it will mount, and where the battery will fit. How to attach a sprocket to the motor will depend on the precise motor but a competent welder would be able to do that step for you, and you can buy chain and a chain link tool from any bike shop for not very many local currency units :) If you have more specific queries I'm sure one of the experienced E-bike builders will be able to help you.

yeah i think u need to specify the size of drill, my whipper snipper motor powered my bike comfortably, but it wasnt fast and definatley didnt have moderate torque lol, if ur thinking of a hand drill i think you have no chance. If you had one from a bench drill or sumthin it wld go but wld be 240V AC, my suggestion is a starter motor, check out "electric bar stool racer" on google

Umm I would suggest using a motor from something else, like an old E-scooter or wheelchair...

what size motor is the drill ? I know none of my 3/4 inch drills would move a bike (unless there was no one on it).

Does this link on hp vs torque help ?