I came home from work last night, shut off the bike and put her to bed. As I was doing this, I noticed a low sounding hum coming from my hypercharger, possibly the throttle body. Any idea what this might be? I never heard this before.

 

You sure it wasn't from the fuel tank? The wife's bike does this at times and I believe it's the pressure relieving off the fuel line......

 

It could be that. The sound comes from around the tank area.