Yeah, measured at the leads that connect directly to the pump motor (pump unplugged). Pump harness is connected to the bike harness. The 6V comes on with the flip of the engine kill switch, so the current behavior seems correct (just incorrect voltage output). I'll remeasure the voltage at the bike harness connector with the fuel pump disconnected, isolating the pump system from the rest of the bike. I'll also see if I can't measure a resistance through the wires in the fuel pump system itself, but it seems like the issue is on the bike harness side, just no idea where. Is there a way to jump the wires at the ECM connector to create a running condition? i.e. jumping pins 1 (gray) and 3 (brown w/yellow)?

I'll also, for good measure, go through and clean up all of the ground connections on the bike to see if that's causing a problem somehow.
This is all really throwing me for a loop and not expected when just changing out a battery. Does the regulator or anything need to be submerged in fuel for any reason?