An inexpensive 600 watt curry motor.
Allelectronics site has a lot of stuff . motor controller,throttle chains, and belt driven stuff.
24VDC 600W MOTOR, 15T W/CLUTCH | AllElectronics.com
A very good throttle controler
#908 Twist Grip for Electric Bicycle - $29.95 : Zen Cart!, The Art of E-commerce
I do not like lipos.
100 NiCd Sub C 2200mAh Batteries for PowerTools No Tabs - eBay (item 330329794886 end time Oct-09-09 10:46:15 PDT)
For this link let the buyer beware. It looks too good to be true to me.
I have no relative reference to judge this guys claims.
If this is TRUE it would kick some ass ., ERR very fast.
How to Convert an Alternator to A Motor - Page 11 - RC Groups