My friend has a 98 wr400 with a Clarke high capacity tank...I think it is a 4 gal. Last weekend we were riding some single track and hitting some jumps. His bike stalled on a landing and he heard this hissing noise. He opened his tank and all this preasure released. He looked inside and the gas was moving like water before it starts boiling. sure enough the tank was supper hot. There was < 1 gal left in the tank...he has never gotten that low before. Anyone seen this happen before? How dangerous is this?