I doubt that this is an easy fix. The twin cam bikes have a valve in the pipe between the cat' and the exhaust can which, I suspect, both works like an ExUp valve, ie it maintains gas flow speed when it's partially closed and also allows for a freer flowing and hence louder exhaust when it's open.Thanks. Thought so. I prefer the quieter one.
Are they a straight replacement.
Are any after market ones quieter?