General range of increase in HP from porting/muff mod

[jon lambert]

Back in the '80s I had a 79 rd400 Daytona special ported and Polished the funny thing was the thing that changed low end top end power was my exhaust whatever Chambers I put on it and what the Jets were had nothing to do with the porting of the motor how you put it the motor it was all in the exhaust Port the way that the exhaust note goes bac
k in and charges the cylinder it's exhaust systems that make the power