The most common differences between regular motorcycles and pocket bikes are the size of the machine, its engine displacement and the equipment that comes standard on the vehicle. Pocket bikes are not legal in many states because they do not have a seat that rests 25 inches above the road.
The overall size of the machine, including its seat height, is a major factor in whether a bike gets classified as a pocket bike or motorcycle. Many states require a minimum seat height of 25 inches to protect riders, which only the largest class of pocket bike is likely to attain. This class, commonly referred to as the super class of pocket bikes, is no longer legal for import to the United States, as of 2012, due to safety concerns. Engine displacements for pocket bikes typically fall at 50cc or less, while motorcycles typically have much larger engines.
Pocket bikes are also considered illegal for use on public roads in many areas because they rarely have all of the equipment required for motorcycle operation. This requirement includes working headlights, turn signals, a speedometer and a horn. The small displacement of the engine can also prevent a pocket bike from attaining safe speeds on roads shared with motor vehicles.