Motorcycle Repair: noise?, bigshots, gas tank

Question
I just picked up my brand new 2006 Dyna Street Bob, yesterday.  Rode home with it about 40 miles. I was out for a ride today when about 10 miles out, I heard a noise. At first it sounded like sand or pebbles being thrown up against the engine. It got louder. Sporatic and more like something rattling inside the gas tank. Almost like a chain slapping the inside of the tank. A loose hanging chain. There is no noise when the engine is revved in neutral. I noticed the tank was getting low, below 1/2. I thought maybe a link to the fuel guage was the culprit so i filled the tank to see if there was a change. It continued for about 30 sec then stopped. Could this have been pinging, or valve noise? My bike has Vance & Hines Bigshots dealer installed and I assume the appropriate other changes to go along...hi flow air filter, I don't know what else may have been done. there is a total of about 125 miles on the bike. When I topped the tank I used Hess premium. I continued to ride for about 1 hour and did not hear the noise any further but I'm concerned nonetheless.  At one point it sounded like pebbles being thrown up against the inside of the tank. I know that it is hard to isolate noises while underway, and being new to this bike doesn't help. Perhaps you can shed some light on this.Thanks!

Answer
I have noticed that when I put new tires on bikes there is a little sticky on the tire from the lable which will pick up small stones and they hit the fender. After a while the sticky wears off. Never the less, I would keep an eye on the bike and if the sound comes bad take it in and have the dealer do a dianostic on it
Good luck and happy riding
Mike