I have a non-California '92 GRX-R 750 and just found out the gas tank I bought on Ebay may be a CA model. It has a very large breather tube nipple (1.75" dia.) with a check valve in it. There is also an extra fitting with a tube and small black plastic right-angle connector/valve (perhaps?) on the rear underside of the tank. Does anyone know how to deal with this?