If anyone still having this issue Mine did the exact same was riding put the bike in neutral and it revved to the moon kill stwitch doesn't work i switched my carb with another bike same issue. played with the tors idle screw and air screw managed to get the very high revving down but that still never fix it 100% i saw a thread saying to spray starter fluid or carb cleaner so decided to try it since it was laying around and surprisingly the right side of the intake boot has an airleak bike starts to rev itself when carb cleaner is sprayed there