Motorized bicycles are a relatively new category for bicycles. The idea is to take just about any bicycle and install a motor kit. There are gas or electric powered kits available in the market to order. The key to turning a standard bicycle into a motorized bicycle is to make sure your bicycle frame has big enough dimensions to accept the gas motor. With electric bicycles the motor is usually built into the wheel, and so a rack for a lithium battery is required to power the motor.