Teflon, I took mine to reserve for the first time today and got 111 miles. With a 7.5 liter stock tank, I calculate tank dry mileage at about 150 miles. There are some differences with my bike though because it is the motard model (D-tracker, sold only in Japan) which has less teeth on the rear sprocket. My engine and exhaust are still stock. When I finished my ride home from work today, I laughed out-loud thinking about how much fun I'm having while getting 76MPG!