Thanks guys. Next question. What is the difference between the offroad .21 carbs and the onroad .21 carbs (Novarossi) ? The offroad carb body is plastic and the onroad is aluminum but what are the actual performance differences? At one time I heard that the plastic body was to stop the fuel from being heated as it entered the motor. We generally ran the on-road motors hotter so to me it doesn't make sense that they would have the aluminum body.