83 XJ750 Seca

Hi guys, I haven't been around for a little while, but I have problem I could use a hand with.

My bike won't start. Hit the start button - nothing.

Current is passing through the start button so that isn't the problem. 3 of the 4 wires in the starter cut-off relay are carrying 12 volts, the 4th wire (one of the red/whites) has nothing.

The two small wires on the solenoid (blue/white and red/white) are both carrying very small voltages, I'm not sure what they should be reading.

No power is getting from the solenoid to the starter.

I opened up the solenoid and cleaned the contact points. Beyond that I'm not sure what to do.

The problem has to be either with the solenoid or the cut-off relay, but I'm don't know how to determine which (I'm still a little confused on how the system exactly works).

I'd love any advice you may have. Thanks guys! :)

An added note:

If I jump the solenoid the starter spins the engine but it doesn't fire.