re: Balance pipe

[Kent Christensen <lkchris@uswest.net>]

Among other things, a balance pipe effectively enlarges the
size of the exhaust system.  If it's a dual exhaust system,
then the size is almost doubled since right-side cylinders
get to exhaust into both left and right pipes and vice
versa.  The concept is really easy to visualize on my BMW
twin-cylinder motorcycle, which has two crossover pipes.