Not sure if this is your issue or not, but the stock stereo system has some type of elevated (floor noise) that has a white noise at lower volume. Most of us never notice it at all because of the bike running and usually have the volume up, I discovered this when I started to upgrade stereo and added intergration-and higher wattage amp. I would assume your hearing this now that you have it to your ears? Just turn your bike on to acc and not start it, with the stereo on turn volume all the way down you will hear it -may have to put your ear up to the speaker grille. See if that's the same noise your hearing.