Just hacked a stock exhaust for my trac DP50 2 speed. Put it onto a 2 piece Biturbo I had around.
First run I extended the expansion chamber as far as it would go.
Bike maybe a little faster on the top end.
Second run moved the chamber in half way.
Still a little faster.
The biturbo header is short, should I cut the Trac header down to the biturbo's size, or is there a way to test the best length before I make any cuts?