Haynes Motorcycle Electrical Manual – you need this book.

A VERY comprehensive manual, this covers everything you'll need to troubleshoot the electrical system of your motorcycle including the fuel-injection system. You will find chapters on ignition and combustion, spark plug types and construction, ignition, magnetos, coils and batteries, CDI, transistors and digital fuel-injection, engine management, alternators, DC generators and starters, lighting and signaling, braking and traction-control systems, electrical fault-finding, practical testing and test equipment.

Good for both beginners and those with more advanced knowledge. Even if you aren't mechanically inclined, this book will help give you a good handle on the electrical system of your bike.