Just having a little fun with ya Maybe you got confused with the Active Intake System (Japanese only) referred to in section 1 page 44 (E1 supplement)
The muffler system on XB 12's is technically referred to by Buell as the Interactive Exhaust System. The Interactive Exhaust Cable, and Interactive Exhaust Valve. You'll have better googling answers using the proper terms
That said, if yours is inop there is a good fix for it that replaces the plastic gears that strip with metal ones. Our esteemed Lunaticfringe has the deets. Search under his screen name and should be easy to find.
Or, if yours is just missing, they are easy to find. Most people take them off when adding a performance muffler.
Heres a dozen or so for $20-$30...
https://www.ebay.com/sch/i.html?_fro...Desc=0&_sop=15
And to make up for the smartypants-ing
https://www.bettycrocker.com/recipes...5-d40b1950db20