dginfw
If your dealer is anywhere close to you, you probably should take the bike in for him or his mechanic to hear. Make sure they ride it a block or two so they can actually hear what your talking about. Just standing next to the idling bike won't be the same.
They will probably say it's a normal sound but being a new engine there are some things internally that could cause that sound if the factory left out a cir-clip or something inside cracked or broke.
Doing this also puts your bike on their list so if anything really does go wrong you can say, "I asked you about this and you said it was fine. Now, please fix it."
I'm not saying anything is broken and a leaky exhaust right at the head would be my first guess. If it is, ask the dealer to fix it. Then, as the others suggested, keep your eye on the area to make sure it's not loosening up.
Speaking of loosening up, at a minimum, weekly and better than that, daily put a wrench on all of the exposed bolt heads and make sure they are tight.
Big singles, especially during break in vibrate a lot and can loosen even the tightest bolt.
If you find a loose one, remove the nut, apply some blue Loc-Tite (or other thread locking compound) and retighten it.
Loc-Tite is our friend.