As shown about halfway down on the link, p/n 76-6312-B in 22mm for the Valk tank. I've looked at a number of their distributors and don't find it....as yet anyway. Using it on the GL1200 project to which I adapted a Std. Valk tank to mount and fit. Just want to run a line over to the side, then pick up an inline fuel cutoff from Aircraft Spruce....$11. Was going to try using my spare Valk petcock and control but the petcock is too far back and is hidden by the frame. I did fabricate an extension for the Valk control using a universal/socket combo to slip on the petcock. It works but looks crappy so want to come up with something else, functional yet simple....or vice versa.
http://www.golanproducts.com/fuel_valves.html