How do you tell what it is a scooter or small bike?

If the engine is 49 cc or smaller, then it is a scooter. If the engine is larger, for example 60 cc, then it is a small motorcycle. Anything above 50 cc is no longer a scooter. This is a legal definition that has to do with which category a motor vehicle on two wheels belongs to. In most people's minds, however, a motorcycle with a 100 cc engine is considered a small bike. This is because motorcycle producers have steadily been producing bigger engines over the years. In 1966, the Honda CB 450 was considered a motorcycle with a large engine. Now, a 450 cc is just medium sized.