Many people purchasing the 2007 touring models have found that there is a problem with noises much like a can of marbles when riding in upper gears with lower RPM's. Some say it's lugging the engine but it goes deeper than this with the taller gearing that is in the 07 bikes only making it worse for the rider.
Here's a page to explain the problems and don't forget to explore the other links at the bottom of this page also.

Lots of good info here.

http://www.coolclimbing.com/2007harleydavidsonroadkingclassi.htm

I suppose I was lucky.,..1400 miles with no issues other than a noisey drivetrain as compared to the Vulcan 1600 I traded on my 2007 FLHTC. Plan to install the IDS after awhile and that should resolve the noise issue. Good luck to all..( I have a buddy with an 07 Sofail Standard..5000 miles with no issues )