Hello- Just wondering if anyone out there has had any sources for or success at fitting an aftermarket petcock to the 77/78 750 tanks. These have what I belive to be a 16mm bung on them. There is an ample supply of harley products but they would most certainly require an adapter (which I have not seen) and I am doubtful as to whether the intake tube / filter assembly would be small enough to fit into the existing hole in the tank. Any thoughts?