'04 CRF250X RPM's will suddenly increase by about 3,000 at idle or while riding when throttle is released. Throttle cables are lubed, clean and have POSITIVE return to closed position! Carb has been removed and had all orifices cleaned with carb cleaner and blown out with compressed air 3 TIMES! I re-jetted this carb while I had it out, but this problem was occuring beforehand! Pretty scary to release the throttle and have the RPM's increase while out riding. This occurs MANY times while riding, but NOT everytime! HELP!