Radio hum

[bagelboy]

I got caught in a heavy rain last week, and since then my radio continuously makes a humming sound regardless if it is on cassette or FM. I switched out the radio for another on my other 1200, and it turns out the sound is not the radio, but the bike itself. It hums if the bike is running, or if the bike is off and the key turned on. Another words, whenever the bike battery is switched on. I know everything is pretty much dried out, so I don't have a clue what the sound is. It appears to increase if I turn up the volume on the speed sensor, or whatever you call it. Any ideas?