Simple test light. Connect the light to the battery+, key on,put the probe in the yellow/red wire, push the button. Does it light? If so good. Put the probe in the green/red, does it light? If it does you have a problem on the ground side. Does the neutral light work? Try it with the clutch pulled in. If you have power on the yellow/red and not on the green/red and it still doesn't click the solenoid is bad. If it does click but nothing happens touch the probe to the wire going to the starter, if you have power the starter is probably bad, if not the solenoid is bad.