Mine will do that too. It also stalls if I take the choke off too fast (the motion, not the time) but once I take it down the road it's fine. My Honda air cooled dirt bikes did the same. Just won't go until they wanted to. I just wrote it off as an air cooled carbureted bike thing. Mostly that certain parts of the motor just weren't warmed up yet so the mixture was off.
Or maybe the damn thing's broke.
It's eight and a half gallons of gas; and an engine. What more do you need?-- BMW R80G/S
Save lives. Legalize lane sharing.
Cow eyes don't glow.