My 2011 Road King makes the exact same sound. It's done it since the day I got it. Never gotten any worse after about 2500 miles so I finally just wrote it off as "normal".
Thank God for this forum! I just took my 2011 street glide into shop for service, and while there asked them to look into this same thing. Service desk kid looked at me like "huh"?
(Service writers need a bit more exposure in my opinion.)
I feel much better knowing this is "normal".
BTW, noise started around 95 degrees outside after about an hour of straight riding. Had it a year and never heard before now. So, wondering if heat induced reaction in the rubber belt?
Its likely your tires, 2200 miles is about when my tires start singing. Next time you are riding, listen to the whine as you take a curve, or cross lanes. The pitch of the whine should change because you are riding on less worn rubber.
My '09 did the same thing, began about 6000miles. The first two times to the dealer they said can't find anything wrong or hear a noise. Third stop in i was told my rear tire was cupping... took to an indy shop and had a set of metzlers put on... PROBLEM SOLVED!!!!