I am completing a k-bike built from parts purchased one at a time on e-bay. It's been a fun project, however I have hit a snag. While I've tried to use 1985 parts the wiring harness has what looks like the original tag "tank" on one of the connectors. The harness plug does not match the four prong connector under the tank. I'm assuming the tank and harness are from different years. Would anyone know which wires match?