All the bulbs were already removed from the bike before posting with the exception of the speedometer odometer bulb that I can't remove (but I unplugged it). As mentioned, I disconnected all wires to the engine, the blinker relay, the CDI and the diode. I've also disconnected individually many other wires and as mentioned in my first post, the only one that seems to stop the problem is when I disconnect the black wire that comes through the frame at the 4 way connector by the handlebars but I suspect doing so is essentially disconnecting everything at once? The only place I see a black wire coming out on the rear end of the frame tube appears to be going to the blinker relay (round aluminum can). Again, I checked all the switches and buttons and components I could think of up front as well as isolating all the rear lighting too.....I just don't get what the heck could be causing this. I highly doubt there is a break inside the frame tube and all the wiring entering and exiting is well wrapped from the factory.