> This was a used solenoid
I believe the most common reason for removing a used solenoid from a bike is that is does not work anymore.

If the solenoid clicks, the start motor is good, because the coil in the solenoid gets power over the thin cable and ground via the starter motor. If you connect the two thick cables at the solenoid with a strong screwdriver, the start motor must spin, even if the start button is not pressed. When you press and hold the start button and then connect the two cables, the engine should start. Conclusion: Throw solenoids away as far as possible and get a new one.