|Here is the 2-D CAD file:
This is a flat-lander (2-D) study of a three-valve head. The cylinder
base is traced off a 1000cc iron head. This is intended to be an
Four valves head don't work well on air-cooled engines since there is so
much exhaust port surface area. They tend to overheat and the exhaust
valves run too hot and cause pinging.
A three-valve head with two
intakes is much more practical. It also allows better squish and a place
for dual spark plugs. This design was a study. There is no rocker or
valve actuation to go with it.