Fugg me this question 13 years on !
This is the "Active Exhaust" in Harley speak , it is NOT on US "Domestic" bikes only on some market 5HD vin numbers including EUROPE
We in Australia get the Euro spec bikes 100% ( bar the LHD headlights !). Have done since October 2006
I said the 'zact same thing to Frasers HD in Perth in October 2006. "What the fuggzthat ?" Re my new 2007 FXSTC just arrived in Oz
AND THEY DID NOT KNOW I KID YOU NOT !
So I found out and told 'em you betcha. I Worked out you could "fool" it and not trigger a fault code by just screwing or riveting the flapper in the open position.
So I tells Frasers and they started doing it at PDI on many bikes. I did many bikes for mates , and 13 years on they are still running allright, flapper screwed open.
I have now worked on many "Grey imports" both from the USA and Japan and they do not have this "Active exhaust' system. ( we also get "active air" they don't !)
It is not to increase torque , it is purely for Euro spec "drive-by" noise testing while you are in metro areas like Paris for example.
They strangle the bikes to buggery and always did.
If you change out the stock headers , as in fitting a V&H system for example you just unbolt and unplug all that bullshit along with the stock exhaust.
If you have a "race tuner" for the bike then there are calibrations or "'MAPS" that allow you to switch off or more accurately "disable" active exhaust and air.
You may then have to over flash the bike again with a calibration for your model/cams etc etc. Not all calibrations allow toggling OFF and ON