I just bought an 06 kx250f and the second time out riding I noticed this problem. Not thinking much of it being a new bike, may be it still need to be broke in. I stop to check the oil no oil. Where did it go, a bolt backed it's self out internally inside my crank case and was flung through the case. Had a hold just below the carb about the size of a dime. Kawasaki admit to fault and replaced everything for free. Has anyone else had this problem.