I have a 2008 street glide and i recently took it in to my local HD dealer for the 10,000 mile service. after i picked it up i noticed a slite pulsing vibration in it. i immediatly took it back to the service dept. and told that something was definitly diffent with my bike. they took it for a test ride and the mechanic said he couldn't notice any significant problem. does anyone know what they could have done to cause the problem?