Old thread from 2011 but more can be said about gas caps and tank venting
Even though these china girl 2 stroke gas caps don't have a vent valve other M/Bs do, like the Whizzer M/B
If ya got a gas cap with a vent valve that ain't venting just remove the vent valve by bending the two metal tabs up that hold the vent valve in and remove the vent valve. The gas tank will vent now
If the gas tank makes a woosh of air sound when removing the gas cap the gas tank isn't venting. Other signs of a non venting gas tank is the bike seems starved for fuel
Even though these china girl 2 stroke gas caps don't have a vent valve other M/Bs do, like the Whizzer M/B
If ya got a gas cap with a vent valve that ain't venting just remove the vent valve by bending the two metal tabs up that hold the vent valve in and remove the vent valve. The gas tank will vent now
If the gas tank makes a woosh of air sound when removing the gas cap the gas tank isn't venting. Other signs of a non venting gas tank is the bike seems starved for fuel