I hear this sound when I take mine off, but it hasn't caused any weird problems with running. It sounds like the gas tank is under preesure because of the hissing sound when I take it off, but I mixed up some soap and water and put around the gas cap to see how bad it was, that's when to my surprise it sucked the bubbles inward meaning the tank created a low pressure instead of a high pressure. What does it mean ? I don't know, but I'm very interested in finding why my tank isn't pulling any air in causing it to create a vaccum.

 

I just went out to check for hissing. I flipped the lip of the ATV cover off the back bumper and it snapped forward. I began to roll it up to put it back in the box it came in, and the ATV cover began hissing! It growled, and small sharp spikes came through it and they scratched my hands and drew blood. I guess there was a cat sleeping in the recess of the ATV cover, that got trapped when I removed it.

Although my ATV cover hisses, my fuel tank does not hiss. I would hate to have a cat in my tank.

Your tank is supposed to have some kind of functioning breather hose to equalize the pressure. This pressure (or vacuum) is responsible for some people's quad not starting. There is a check valve somewhere that gets stuck or clogged on some people's 650s. I heard of it but don't have any experience with it.

If you are concerned, just follow hoses til you find the valve. I read some dealers just remove that valve thingy. Wear thick gloves if you suspect there may be angry housecats under the fenders.

 

LOL!!, Nyroc, you're right I went backed and looked at the gas tank after I read your reply and there it was, a Artic Cat was caught between the gas tank and storage box, thanks for the help.

 

Traihog,,,I was talkin' to the dealer up here today.He told me that the valve in the fuel tank vent is designed to hold 3psi in the tank.Apparently this can be enough to push fuel past the float needle in the carbs if they're not seating just right.He said to shut off the fuel when transporting the quad or when it is sitting for a while(overnight or longer)

I haven't had trouble with mine yet.I think it might start getting to be more common as more machines get a little older.maybe Kaw will come up with a solid fix for this problem soon, but for now my dealer says they are just saying to shut off fuel.[img]i/expressions/face-icon-small-confused.gif[/img][img]i/expressions/face-icon-small-frown.gif[/img][img]i/expressions/face-icon-small-shocked.gif[/img]

 

Yep, mine does the "snake act", too. There is supposed to be residual pressure in the tank. It is normal.

 

I've noticed excessive pressure in the gas tank when it is low, say a half tank. I've also noticed gas coming out of what appears to be a breather tube in front of the air cleaner box. Has not had any adverse effect on the engine performance. I just try to remember to open the fuel tank after I've ridden longer distances. If there is a pressure relief valve, I think mine is not opening at 3 P.S.I. as described in this thread.