So it doesn't even click or clunk when trying to start? Just nothing? Yeah, maybe starter solenoid is bad. Or wiring, or wiring connections. If the "bendix" doesn't move out and engage the gears, it would just spin, without engaging the engine to turn. I think I'd jump the connection up on the handlebars, at the starter switch wiring, to make sure it isn't that switch. You have to worry about the gear position neutral sensor also, causing it not to turn over. I'm not sure if that one is normally open, or normally closed. But should be able to bypass that one to check it also. And the kickstand switch, same thing there. If you got those things. Most of these guys would probably say go check the kickstand switch first. They go bad often.