Fuel pump wont turn off

The bike is a 1983 VF750FD. My prob is that the fuel pump will not turn off, after initially priming the fuel system. Constantly running. I shorted out the fuel pump relay by bridging the black and white wires and the pump just runs constantly. Ive got another VF750F, and have swapped both the fuel and fuel pump relay over which has eliminated those two, as there was no change.

Whereabouts does the fuel pump get the signal from, telling it to turn off once the fuel system is primed?

Hi hoges, the fuel pump stops when the carbs are full, it is a low pressure pump, when the float valves close in the carbs that stops the pump,
Sounds to me like your float valves arnt shutting off properly, or you have a restriction in the petrol suply between the tank and the pump,