Sweet dude, you gotta start'em young. You can work on the importance of gear when he gets a bit older. I still wish my dad would have pushed sportbike racing on me as a kid rather than football. No telling where I'd be today!
i started on my 1st bike when i was 6 it was an old school XR75 Honda, ya know the one with the real clutch...picked up moto-x and went from there to freestyle MX to Freestyle Street.....nice pix man just raise em right and keep em into bikes and they'll stay outta trouble....my dad used riding as incentive to keep us is line and it worked great good lookin kid man my lil girl just turned 5 mos so maybe they can 2 up