There are a couple of options

vintage motorcycle or fresh off the showroom floor

A reproduction of the Lucas tail light found on many British motorcycles of the 1960's

as well as Triumph and BSA triples 1968 to 1975

They are 1018 cold rolled steel for easy welding and are great for mounts of all sorts

1/4 inch NPT Mini Petcock 90 Degree Outlet - No Reserve Subcategory_Clutch There are a couple ofThese 1 4" NPT mini motorcycle petcocks have no reserve and feature a solid on off ball valve for a long, reliable life. These small petcocks tuck up under your gas tank for a real clean look. Features a 1 4" NPT thread on one end and a 90 degree outlet with a 1 4" hose barb on the other. Rugged steel construction with Zinc plating. Viton O ring stands up to most commonly used fuels. Sold individually.