I just bought a 2003 XR70 for my son. It had been sitting for a year so the gas had gummed up the carb. I took the carb apart and cleaned it out (twice) and now have it running. It starts and runs well. The problem is it doesn't "back off" when you let off the throttle. It kinda revs along for a few seconds before it slows back down. Needless to say this is not good for a beginning rider. I've played with the two adjustment screws on the carb and am wondering what the screw that isn't the idle screw should be set at. It was at 3/4 turn out and I've tried a few other settings but it still deson't "back down" when you let off the throttle. Thanks for the help!