The first step in building a motorized bicycle is to find a strong, sturdy bicycle frame that can handle the added speed that comes with being motorized. If you use a gas-powered motor, the bicycle frame must be large enough to have the motor and other engine components attached to it. An electric hub motor can be attached to your bike in place of either the rear or front wheel.
A beach-cruiser style bicycle is an example of a strong frame that has ample room to add a gasoline motor. These bicycles are made of steel and feature large diameter tires that perform well at higher speeds.
Choose a motor that fits your bicycle and is of the appropriate power for your intended use. Following the manufacturer's instructions, attach the motor to your bicycle, as well as any additional components such as fuel tank, drive sprocket and fuel lines. Ensure that the drive train is aligned properly so that engine components will not interfere with operation of the bicycle.
If using an electric hub style motor, insert the electric wheel in the appropriate place on your bike, and attach additional components such as the battery, throttle and throttle cables to your bike. Complete conversion kits typically include all parts necessary for the conversion.
Before using your new electric bicycle, test ride the bicycle in a safe, open area free of obstructions.