It is totally normal. I had a YSR I was working on in my basement one year that did it. I took me weeks before I figured it out what it was.

Faerge[}]

 

gas exspands in the tanks and its air from inside seeping out the rim.
if you ride alot and in hot wether good thing to do is open gas cap for a sec when u stop ull here a whoosh of air come out or a silte
pup .its normal

 

My zx9r, 6r and gpx250r have all done that as has my mates zx6r. Its fuel vapor. Ive seen fuel come out of the tank of my mates zx6r on a hot day when it was sitting in the sun!

 

When my bike does that around people, I tell them my bike farted

 

Yea, it is just expanded gases in the tank trying to escape. (Like a pepsi bottle when you first open it) It does this A LOT on HOT days.
Just pop the cap every now and then to release the pressure.

 

Yeah what I usually do when I hear that whineing sound is stick the key in the hole awhile, and get out a lighter, Then light the lighter right near the hole, and then turn the key!



j/k [)]

 

Is it still normal if it does this for an hour or more? Also if I open up the cap and then close it back up it will start back up.

 

In addition to the vent hose on the bottom of the tank there is a little vent hole in the gas cap itself. That's the one that makes the noise and it is normal. If a little gas come out it is an indication that you have filled the tank too full.