Let me try to explain some simple characteristics here
first.. water and air have ALOT of the same flow
characteristics.... they dont like to turn... look at
a flowing river and where the deep water is in a curve
in the river... its the outer radius... this is the
reason all these new heads have raised ports, its
trying to make a straighter run.... the short turn in
the head has water under it so you cant eliminate
that corner... then the air makes the big turn in
the bowl and if you look at the area near the seat
(just below it) there is usually a lip there.. thats
the a damn which hurts.... also understand that the
air is going into the cyl because the piston created
a NEGATIVE pressure(some call it a vacuum) but the
atmospheric pressure it pushing into the negative
pressure zone.... ok that class 101