What is this strange "whistle-like" sound that happens after turning off the bike?

 

I must be deaf. I didn't hear any whistling sound.

 

Are you talking about a little squeak (my thoughts) right after shut down that lasts a second or so?
Vacuum leak ???
For S&G take the gas cap off and see if it's any louder.
Just throwing S to see if it sticks.

Is the noise coming through the speakers ?

WP

 

piston quiefe, depending on how open or closed the intake valve stops on shut off, it may fart a little pressure out the intake. but I could not hear anything abbey-normal

 

I can here a very slight squeek.
Kinda sorta like a fuel shut off.
Is that a California bike? with some extra pollution control stuff?

 

I don't hear anything abnormal.

 

Yes, it's a tiny squeak at the very end of the video. It seems MUCH louder in person.

No pollution gizmos and the radio was off.

A "piston quiefe" !? LOL that made me laugh, but it makes sense.