I recently noticed that while my 03 wr450 is warming up, with "choke" on, that the bike occasionally blows white smoke out of the exhaust. (oil?) Its not constant, it only does it four or five times, for a second or so, while that choke thing is engaged. When I take choke off and idle normally it doesn't blow any smoke, but when I crack the throttle it does. After a couple miles of riding, it doesnt do it at all anymore, idling or cracking the throttle. Only happens at the very beginning ater starting it. Whats going on here? Am I screwed? I know that I need a valve adjustment in a little bit, its not bad at all yet. Could that be it?