Re: carb as a muffler?
i have 2 friends that used to drag race motorcycles ( i wont give up their secret ) but they would argue quite convincingly against having zero back pressure , even an oversized unrestricted header tube adds back pressure , and every bend in the tube also adds back pressure . Burnt valves come from running lean ( fuel-air ratios )
generally speaking , a short pipe will give you more bottom end and a long pipe will give you more top end power
every setup needs proper jetting for optimal performance .
i totally tore down and rebuilt my yamaha roadstar engine myself to repair a faulty stator shaft . i run a wide open k&n intake , ported my own rubber intake manifold , and run a 3 inch exhaust . i do my own jetting . I USED MY BUDDIES SECRET and i added more power , and increased my mileage by 75 km per tank