Yikes, Japan don't play around. A suspension over here is simply "you don't come to school until further notice" - a temporary expulsion essentially.
We do have something similar to this called 'isolation', but it's still nowhere near this level. It's essentially a normal school day but you spend the whole thing in a seperate room where no talking is allowed. It's only for serious cases like assault though.
Incidentally, was riding a motor scooter grounds for suspension because it's illegal, or simply because it's against school rules? If it's the latter, why would that be the case? I know Japan has some strict rules about how you present yourself but why would riding your own vehicle be part of that?