My '99 Dyna Sport has developed a chirping/buzzing sound somewhere in the front. The sound kicks in when the bike is underway. It seems constant regardlesss of the speed ( like its a vibration of some sort). It stops if I put the clutch in while moving and let off the throttle. But if I rev the engine while the clutch is in and the bike is moving- the sound kicks back in. There is no noise if the bike is stopped and the engine reved - it only occurs when the bike is moving. Any thoughts?