What is a Scooter?

Well, here's what Wikipedia has to say:

A scooter is a style of two-wheeled motor vehicle traditionally defined by characteristics such as a step-through frame, wheels less than 16" in diameter, a

nd an engine located below the rider and to the rear.

That pretty much sums it up. Motorcycles have an engine mounted in the middle of the frame with a gas tank above it. The rider sits astride the engine with the gas tank right in front of them. Motorcycle wheels are also typically larger (over 16" diameter) than those on a scooter. Another major difference is that the engine of a motorcycle is attached to the frame, while on a scooter it is usually part of the rear suspension. So when a motorcycle rear wheel goes up and down, the engine remains stationary, while when the rear wheel of a motor scooter goes up and down, the whole engine and transmission moves up and down with it.

These days, 99% of scooters have a "twist and go" automatic (CVT) transmission, which means you don't have a clutch to control and you don't have to change gears, while 99% or motorcycles have a manual clutch and you have to shift gears manually (with your left foot). This also means that on 99% of motor scooters you apply the rear brake with your left hand, while on 99% of motorcycles you apply the rear brake with your right foot. While there are still a few manual scooters and there are a few automatic motorcycles, both are very much the exception rather than the rule.

These differences result in a motorcycle usually having better acceleration high speed handling characteristics, but a motor scooter is often more maneuverable at low speed and is easier to ride, especially for novices.

Scooters usually have a small engine, from 50cc to 250cc, though there are 400cc and even 800cc scooters, so engine size doesn't define them. While most are limited in speed, scooters with a larger engine can exceed 100mph and cruise easily at freeway speeds, so speed isn't a defining characteristic either.