I bought a 36V 350W scooter from Craigslist today for $25. With all the rust and decaying parts, I don't think I want to use it as a scooter. I'd prefer to ride an electric bike too.
So, I'm wondering what's the best way to mount the motor and add a sprocket to the rear wheel of my bike. I've seen examples, but I'm wondering if I can do it with just the motor and a large sprocket. I know a hub motor is the simplest way to go, but I've already got working batteries, a controller and motor. It'll be a shame not to put them to good use.
Check out these links:
http://www.bikeengines.com/
$650 kevlar toothed belt 40cc, kit only, no bike
http://www.spookytoothcycles.com/content/view/143/1/
$450 cruiser bike plus engine kit, assembly needed
http://thatsdax.com/
$190 2-stroke bike engine kit
They might sell you a replacement "left side" freewheeling large-diameter sprocket by itself. I've considered this option to mount an electric motor above the rear wheel (Google "Peltzer electric bicycle"). If their small engine sprocket is the one that freewheels (when you're pedalling), that also might be useful.