Welcome to the comprehensive service manual for the 2002 WR400F and WR426F. These high-performance off-road motorcycles are renowned for their potent four-stroke, DOHC, 5-valve engines and advanced suspension systems, making them formidable machines for competitive riders and off-road enthusiasts. Building on a strong heritage in off-road racing, the WR426F, in particular, represented a significant evolution, offering enhanced torque and power to excel in demanding enduro and motocross conditions. The engineering quality and reliability inherent in these models are supported by meticulous design and robust construction, ensuring exceptional performance when properly maintained.

This manual serves as an indispensable resource for owners, mechanics, and technicians. It provides detailed procedures for all aspects of service, repair, and maintenance, covering everything from routine tasks like oil changes and filter replacements to complex overhauls of the engine, transmission, suspension, and braking systems. You will find essential information on electrical system diagnostics, fuel system adjustments, and chassis component servicing. With clear instructions, diagnostic flowcharts, and precise technical specifications, this workshop manual is designed to help you maintain your 2002 WR400F or WR426F in optimal condition, ensuring its longevity and peak performance.