ORIGINAL: Richie-EB4
To test your tank seal..........
Remove the pressure line from the exhaust pipe and remove the fuel pipe to the carb...........empty out any fuel...........then blow into one pipe on the tank while holding the other one closed.........it should hold pressure or it will leak...........more likely the tank lid.
Hope this helps
i did exactly what you said, and i felt pressure when i blew in through the line. so, there is nothing wrong with the tank...