This is why my Blue 09 Ninja was called Shamu ;P
Printable View
Yes this can happen even without running the bike. Temperature changes from night to day can be enough to cause the gas in the tank to contract and expand. There is a pressure relief valve under the gas cap, its just a small rubbery thing and when dirt, wax and stuff get it dirty it will squeal instead of working quietly. Take a can of compressed air and spray around the underside of the gas cap and this will often get rid of the problem.
This happens to my bike whenever I overfill the tank.
There is a really quick and easy fix. Take a hole saw drill bit (any size larger the better) and drill a hole in the side of your tank...It will no longer hiss but you might might find your fuel economy suffers a bit.
thanks again to all those who genuinely tried to be helpful.
Does it on my ninja all the time.
all you kawi guys out there ...just make the hole in the gas cap a little larger than stock, problem fixed. no charge.
My 09 250 would hiss and sometimes whistle. It's totally normal and kinda funny. I kind of miss that sound.