X18 Wiring harness - Pocket Bike Forum - Mini Bikes Jun 12, 2015The problem with wiring diagrams is they don't show where the wires are in the harness. I have an X18, I try my best to stay away from the wiring. Most of these bikes batteries are connect to the system the same way.Author: Matteblack X18 Wire Harness Plug Out - Gas Scooters x18 wire harness plug out this is a the plug wire diagram for an x18 2012 mid bike, it may or may not apply to all other midbikes. please exercise caution when using this diagram, wire colors may not match exactly due to manufacturing variations. make sure to connect your battery last.