Perfectly normal and absolutly nothing to worry about. it is nothing more than compressed air escaping through an slightly opened valve, or you hear the air being sucked into a cylinder by the piston as the intake partially opens when you killed the motor.

 

I have one of them dang bells and mine still does it.

 

Better get that bell checked it's obviously defective.

 

I get the same whooo on my truck with an open cleaner. It's fairly normal any time you open up the airway to a combustion engine.

i need a bell for my brain. Maybe then it will keep me from doing stupid crap to my bike!

 

never on startup, always on shut down.

i've gotten used to it.

like someone else said, i take it as the bike sayin thanks.

 

Gotcha. Thanks for the knowledge.

 

Normal, even my car does it.

 

Same here, at first I thought it was someone whistling at me, either cuz i'm so hot or they like my bike, but then i figured out it was just coming from the bike

 

I thought the same thing!

 

Mine does it at shutdown. People ask me all the time what that was.