Does anyone know how to bench test the stock fuel tap? Before I install the repainted tank I want to make certain the stock fuel tap. I tried to use a vacuum pump attached to the vacuum port. Well...I blew and sucked on the fuel ports but seemed to get closed air on each leg of the outflow ports.. What do you folks suggest? I thank you for your help!
What's the history of the fuel tank & petcock? It sounds like the diaphragm is stuck in the closed position. You could remove the fuel tap lever, then apply vacuum to see if the diaphragm plunger moves.
Hi Martin! I took the tap apart and while cleaning it out I found black "goo" like maybe the spray cleaner melted something rubber in the square part that the screws go through. Also I could not get air to pass through the 1/4 vacuum fitting until I probed it with tag wire and shop air.I managed to get it all cleaned out with shop air. The diaphragm Is in OK shape and I used a small amount of Permatex to seal it up. I'll try again this afternoon with the vacuum to see if I can duplicate the running condition.
There should be an o-ring on the diaphragm plunger where it would contact the petcock body >> it may need replacing, especially if it's hard or flattened or something.
Theres a very good tutorial floating around on restoring these taps. I think from an XS 650 site. worth having a look at it. Somebody here will have a link to it, Im sure.
Also a rebuild kit is not expensive.
