01 Yamaha raptor 660 runs at idle pops when throttled?

Check your parking brake, it will do this if your brake is set. Otherwise, check your air filter, change the spark plug, and clean the carburetors one at a time if the problem still persists.does the machine have a throttle override? I know Yamaha has them on many models. it was meant to retard the engine if the throttle sticks, or by the sounds of it, if the parking brake is left on.