Kwl77

Exhaust port

Intake port. I can see all the machining marks on the ports. Would it be best to polish this before instal.

FFDP

iTrader: (2)

No, I would leave it.

The fuel injector sprays into the cylinder head, some of it hits the back of the wall and back side of the valve. You want the fuel to not puddle up and run down because it will not mix as well with the air.

twigy

You want the intake port to be a little rough as it helps atomize the fuel and mix it with the air. The machine marks help create that small amount of turbulence. Thats why you never see the intake sided polished like the exhaust side.

trxmxzx

iTrader: (7)

I was always told this - “fuel can tumble faster than it can slide”- it’s has helped me remember that for 20 years (2-stroke years)

exhaust side polish to help with carbon build up

Drspencer

iTrader: (1)

Yep, leave it. I don't know of any CNC porter who touches them after the port work is done. Hitting the exhaust side with some 120 grit rolls might not hurt.

ZO6Ted

If the intake at the gasket is smaller than the inside of the port you can polish the top of the port maybe an inch in to match. On the exhaust polish the top of the port to help the exhaust flow. Don't mess with the floors.