I have a 1990 rm 250 and was taking it for a little spin the other day and the throttle or something got stuck wide open. I had the clutch pulled in so I got it into neutral but it was at about 10000 rpm. The kill switch was not shuting it down, I kept hitting the throttle to make it stop. After about 10 or 20 seconds it quit. I let it sit for a few days and then took the carb off and checked everything out. The needle and throttle body seemed fine and it all looked in working order. I put everthing back together and took it out for ride. I ran it slow in first gear and then pulled it into the driveway and slowly started to give it gas in neutral. Same thing happened. It started to rev on its own almost and would not go back down. Kill switch would not work. The throttle at the bars is not sticking. I can not explain this, any ideas. I dont want to try it again until I fix something or I am afraid it is going to blow the engine. Need some serious help!