Joe, it sounds like you have a lot of brake pad drag caused by the caliper in need of service. The brakes should only have a very light drag, which sounds like a light "swish" sound when the bike is moving. If it gives a loud "moan" or vibration noise when you roll the bike forward or back, you need to get the caliper serviced. New brake pads come with Service Instructions, shims & spring clip. But having an HD Service Manual is highly recommended. Also get a bottle of the proper brake fluid (read the type needed on the M/C reservoir). Good wrenching and keep us informed as to your progress.
http://www.hdtimeline.com/brakes_tires_and_wheels/2887-brake_caliper_maintenance.html
I forgot to add, that the brakes are single action, floating caliper type...meaning there is no outward retraction once you let off the brake pressure, the disc runnout (slight wobble) is the only thing that pushes the pads back, retracting piston into the bore, hence the swishing sound.
The caliper floating means that the pivot pin which is lightly greased allows the caliper to be centered over the disc, again "wobbling" ever so slightly so both pads wear evenly, even though there is a piston on only one side pulling the works together.
Thus the drag should be very light, if heavy the common failure mode is slurry of water, dirt and debris get up into the piston area contaminating the bore, as well as the pivot pin area, binding up the works or preventing the caliper from centering, wearing out one pad severely more than the other. And of course the brake fluid gets contaminated with seal/o-ring wear along with the moisture diluting it (water and broken down ethylene-glycol can oxidize and cause corrossion) so flushing and bleeding brake fluid is also recommended....no spongy brake feel allowed.