Our BMP Fatt Azz single pipe is known for being the most powerful single pipe for big bore 800-925cc motors. The neat part about this pipe is it likes to be worked and it has an amazingly wide powerband. This is the pipe we use on our F8 big bores to produce 170-174 HP and well over 180 HP on our F9 big bores. Many other performance companies recommend our Fatt Azz single pipe for their big bores as well. The powerband at wide open throttle is from 7700-8000 RPM so it is easy to clutch and make it haul Azz!! This pipe has an amazing amount of torque and loves it when the clutches work it hard with heavy weights, which in turn puts more power to the track. This pipe is designed to only work with a BMP high flow manifold and fits into the stock muffler or our lightweight Full Velocity muffler. No need for twin pipes any more. Go Fatt. Go BMP Fatt Azz!! Low alt pipe only - high alt riders use BMP Stealth Pipe for best performance.