Downpipes and physics

[midden]

if we want to get really technical, the best pipes have a taper from the exhaust port to @2/3 down the header (it depends on the stroke of the motor) to maximise cylinder scavenging.
a few years back hond@ used oval pipes on the rvf endurance machines, then discovered another 7hp when they fitted circular pipework.
fluid dynamics................fascinating :'(

And the reason you're named sadlonelygit is?  :lol