It looks like for the 87 they combined the fuel pump and fuel pump relay into one unit and called it the Fuel Pump, as for the colors...
GREEN = Ground.
BLACK = +12 VOLTS.
YELLOW/BLACK = Not hooked up to anything.
BLUE = Pulse signal wire from the Spark Unit.
On the 83 to 85 Shadows the blue wire turned on the Fuel Cut relay that turned on the fuel pump when it received a pulse signal from the spark unit, this only occurs when the engine is running or you are trying to start it.
On the 86 and 87 Shadows the blue wire does the same job but the relay is now inside the fuel pump, but since the motorcycle runs if you put gas into the carbs some other way the fuel pump is probably bad or you have a wiring problem. If you do an OHMS test on the blue and green wires you should get some kind of a resistance reading.