The choke is off when it is all the way back. Try leaving the choke on a little longer to let the engine warm up a little more, then turn it off. When you have it all the way on the bike should be on high idle. I think mine is at 2000 to 2500 rpm. Leave it there until the engine is warm enough to run at low idle. I leave mine on for about 30 seconds or so. Try that.