I have a harley 05 ultra classic, that over the last 2 years while wearing my helmet without the radio on I have been picking up a noise that is either static or ignition. The noise increases as the rpms increase. Does anyone have any idea what could be causing this and how it can be fixed. Any thoughts would be appreciated.

I often think it's noise from the brake rotors. As you know I bought a Sportster 48. I kept hearing a distance ambulance siren. It even 'trilled' like some of them do. I think it was the modulating speed of the throttle as I tightened my grip or went up slight inclines.

I don't wear a helmet, so the only thing sucking air I can think of is the front brake rotor.