[kawagumby]

If you are worried about a static spark when filling the tank, wouldn't it be more to the point to simply touch the metal gas nozzle to the headlight housing or other chassis bare metal before filling the tank? This should negate any voltage difference. The tank should be grounded to the frame, engine, etc. by way of the fuel lines and tank bolt connections.


Edit: You can check for the tank being well-grounded to the frame with an ohmmeter, if not, run a bonding wire.