Gas cap whistling


Came back yesterday from a ride and parked the bike. After returning 20 - 30 minutes later there was a strange high pitched noise. Opened the gas cap and "phooosh" and the noise gone. Anyone have any suggesstion on how to allieviate this. Pressurazation could stop the Gas flow at high speed and death is not a option to explore. What can be done?
Ive had a couple of bikes do this to me. Its not gona bother anything while it does it. If you notice it will only do when you A) leave it parked out in the sun for a little bit or B) when you have been ridding realy hard to a long period of time, normaly over three or more hours. Ive been living with this sound for three years on multi bike and have found that the only way to stop it from doin it anymore is to replace the gas cap, the hole thing including the rubber seal. Just so you know, the cap I replace with a factory replace ment ran me 100 bucks for the cap, 10 for the seal and I had to change over the key and and lock before I could use it.

My advice, live with it, no harm will come of it.

Thanks Jester for the sound adivce and info


I had the same problem and the dealer did not know anything, so I researched it and ended up disconnecting the line from the charcoal cannister. If yours is a Ca bike, that is the problem, the one way valve in the vapor return system will not open soon enough to let the pressure pass to the cannister. I had a whole thread on my process on Suzuki Hayabusa.Org, search under "whistling gas cap" or under my member # 1717.