That edge arrowed is worn from the screw and I guess there should be a tab to stop the tap turning 360 degrees ??, the tap does turn right around, have 2 and they both do it, guess that's from years of wear, that's why I changed to the vacuum tap, I didn't know they were different later on with the two retaining screws, might have a look around to see if I can get one of the "better" ones, cheers Pete.
I have gone the easy way, added another shut-off valve to the system. I leave the original in the reserve position and have installed a fuel filter and aftermarket on/off valve after it. The valve is located lower, easier to use and does not leak due to the debris being caught in the filter.
Feel free to copy the solution.
The fuel valve design incorporating a single screw to hold the guts was the original design and had issues. That screw was replaced with a design that utilized a face plate (2 screws) to retain the guts. This was to eliminate the inherent friction and misalignment created by the single retaining screw.
Lapping the cone to the body can repair a leaking valve if the damage is not to deep. A slightly lighter spring and filing down the "Tabs" that fit into the cone, can return the valve to an operative condition. An initial smear of silicone grease on the O-ring and cone doesn't hurt.
1980 KZ 1300 sr# KZT30A-009997
Always High - Know Fear !