I put this on my four stroke yz426f. It helps a LOT with keeping your leg from roasting, and also while idling I've noticed lower temperature readings most likely because its not radiating as much heat under the right radiator. Makes it a little quieter on stock head pipe but not too much. Overall it works great, would buy again. Also make sure you buy some clamps. Note: Does not have to be DEI clamps, auto clams work good too.