You may want to talk to a guy named Jon Vandermueller... His father's name is Don and they own a coating company here in the Chicago Suburbs .. Lo-Ko performance coatings is the name of the company.. Don't be too judgemental on TEFLON COATINGS or CERAMIC COATINGS,,, BOTH have a better thermal limit than what you're coating on them right now.. Remember HARD ANODIZING is a form of PLASTIC and the TEFLON and also the CERAMIC have MUCH BETTER properties.. the reason YAMAHA doesn't use that is because of the COST.. if they make a HUNDRED THOUSAND valves,, and it costs them TEN DOLLARS EXTRA just to TEFLON COAT THEM EACH,,, that's a MILLION DOLLARS that they save by just SKIMPING (or hard anodizing instead of teflon coating) on the valve.. talk to DON or Jon,, they are SNOWMOBILE GURU" and know a LOT about high performance coatings... I've known them for a BUNCH of years.... Gary Oles nosboy