This modification replaces the stock XR600R or XR650L exhaust baffle with the baffle from a Honda ATC 250R, which has a larger opening. The exact baffle I used was from a 1985 ATC 250R. It uses the exact same baffle just with a ~32mm opening compared to ~20mm of stock. The larger 250R baffle is almost as quiet and with just a lower growl. The ATC 250R baffle cost me $5 at a salvage yard and took just a few minutes to switch out.

Credits: Submitted by kubiak to our "Best Low-Buck Mod" Contest, and edited by 4Strokes.com.