My sons got the Takegawa Hyper R stage kit on his CRF50, the bike runs well when it gets moving but on some starts if the throttle is pulled open quickly it bogs and stalls? The carb is a VM26! He is running the heavy duty auto clutch. It's currently running a 17.5 pilot and a 150 main, what are you guys running? I've tried tuning with the air screw but that hasn't worked either.