i was rejetting the kehin carb on my sons 250x and everything was fine until i took the side cover off to move a notch on the needle. i thought i saw something spring out when i was taking the cable off. anyway i made the adjustment and now my jetting is fine but the slide valve while the motor is running does not want to drop all the way down to idle unless you snap the throttle. when the motor is off it appears to be fine. any ideas?