Overall, the Yamaha XT 250 wiring diagram is an incredibly useful tool for understanding and troubleshooting any electrical issue that may arise. Fully understanding the wiring diagram will help bike repair professionals, along with amateur riders and mechanics alike, give the bike the attention and service it deserves to ensure that it runs.. The 1983 Yamaha XT 250 Wiring Diagram is a valuable tool for anyone looking to get their hands on a classic motorcycle. The wiring diagram, which is also known as a service manual, provides detailed instructions for troubleshooting and maintaining your vintage machine. With this wiring diagram, you can quickly identify potential problems with.