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Old 12-13-2009, 07:08 AM   #11
DeutschMark OP
Full Tilt Boogie
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Joined: Aug 2008
Location: Grand Haven
Oddometer: 336
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?
89 BMW R100RS
97 Suzuki DR440
And away we go!
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