Originally Posted by bmweuro
I have built a lot of airhead race motors in the past 25 years and this is an area I would not tuch on a street bike. If you ever rev the motor you will crack a lifter and on the street you will never notice the added performance. If your looking for cheap reliable horse power in a Boxer you can do 2 things.
up the compression and port match the heads.
I've already got the compression part covered. I've got a set of late 9.5 pistons and I'm going to dual plug, so I'll bump it a little more. I also have a Scheffer/Edelweiss asmmetrical cam ordered and already have some Mikuni carbs. This should be a peppy airhead!
When the heads are done I'll have the machinist use 44mm intake valves.
As far as the port matching goes, I pulled the heads and planned to do a little smoothing and casting flash removal, but there doesn't seem like there is much to remove. The intakes are clean, with only a little casting flash. There is a small hump on the bottom of both intake ports that could be smoothed over and a booger size piece of flash on the short radius of one intake. Is this what you are referring to?
On the exhaust side, there is a small step outward all of the way around the area where the head transitions to the spigot. Are there any gains to be had by removing this?