Why is that? From the way I understood it, the tank would only emit fumes if the gas was warmed up (moving inside for example) and it expanded. Once held at a constant temperature, I would think that the tank wouldn't emit much.ducpainter said:Yes they are. If you put the bike in a warm basement the gas tank could vent fumes. Unfortunately an empty tank will cause rust. How about storing the full tank , with Sta-Bil, outside with the bike in the basement?