Wow, I don't know where to begin.
Let's start with the Vespa, it's not a motorcycle!
I guess you could put the Guzzi V8 on there but they made to many great bikes to put that one at the top.
Y2k a motorcycle with a jet engine.
Honda cub is only there because of sheer numbers of bikes made. If I'm making a list of
BEST all time there is no way a cub beats out a Ducati 916.
The CB750, Bonnie, and 916 all belong because they set the standard for their day