I've had a problem with my gas tank a few times in the last six months. After I've filled the tank, if I'm parked on a hill gas pours out of the fillneck. It doesn't do it everytime, in fact it's been about three. I am ultra-cautious about topping the tank off, so I know it's not too full. Is there some kind of backpressure on these tanks? My fillneck is pretty worn were the cap screws on, so I was thinking of replacing it but SOR wants $180. I just wanted to be sure that was the problem before I shelled out the money. Not good for the paint, and the fumes seep in to the inside. Lucky it's summer.