I have searched and am having trouble finding an answer. I have an 06'wr450 with the free mods done. There is no bog and is strong all the way thru. Question is with stock jetting am I taking a chance of burning a valve. I have put on the TT AIS but still have a lean pop when letting off the throttle. I like the way it runs now just worried when a friend told me I might burn a valve if I don't rejet. Also thanks for a sight that has so much info its great!