Grand Prix 500
Main Motorcycle: 2011 800 Roadie
Join Date: Oct 2005
Location: Tacoma, WA USA
Other Motorcycle: 96 Thunderbird
Extra Motorcycle: 2001 Super Sherpa
Leo Vince "mystery disc"
So as others have noted, the disc with holes is a restricter to be inserted between the mid pip and the intake of the exhaust. I put mine in last night and it does reduce the noise significantly. Although it may make a difference on a dyno run, it didn't seem to be that noticeable during my 15 minute test ride last night. Will report back after a more "spirited " run next weekend.
In addition to finding the droning annoying for long rides, part of my motivation is to keep from being overly attractive to law enforcement. Seems to me that loud bikes get more attention from the LEOs. Since I do like to exceed posted limits, why wave a red flag??