1981 xv750 headlight issues

Having issues with my 1981 Virago. I had a stator go bad when I was riding back from work. I ended up ordering a new stator and rectifier. During this time I took the opportunity to put new stem bearings and front wheel bearings in. I also removed the vacuum "gulp" valve and installed caps. During the whole process I would check to make sure the bike would still start and run. Which it did. Up to yesterday when attempting to find the tach signal on the back side of the tachometer while the bike was running I noticed when I probed the Orange wire on the back side of the tach the headlight dropped out. After removing the wire the headlight came back. Now present day, when the key is in the on position headlight is lit. As soon as the bike starts the headlight turns off. I checked main ignition switch it ohms out fine, I even wired around the switch, same result. Unsure where to look next.