polishing an intake manifold on an 883 sportster.?

Question

i had a leak on the intake manifold of my sportster. before i put the manifold back on i would like to smooth out the rough surface caused by casting on the inside of the intake. was wondering if anyone has experience in this area and if it has much improvement for air flow and performance. thanks.

Answer 1

You want the intake to be a little rough. It causes the fuel/air mixture to swirl around and mix better. You want a smooth exhaust so the burnt fuel will get out of the combustion chamber fast. With it smooth, there are no "bumps in the road" to cause any restrictions.