A buddy of mine has a 2004 200 EXC and when trying to smoothly roll on the throttle, somewhere in the low-mid to mid throttle range there is a poppy stutter that just kind of feels like the ignition is cutting out or the fueling isn't right. The reeds have just been replaced and carb cleaned. The problem has been there since he bought the bike a few months ago. It has a new plug. Could it be a gummed up powervalve? He hasn't had that apart. Im pretty unfamiliar with KTM. I know a good amount about two strokes but this has me a little baffled. I would appreciated any and all advice/suggestions.