This workshop repair manual provides comprehensive guidance for the KXR 90, a youth ATV designed for recreational use by younger riders. Produced between 1999 and 2008, the KXR 90 is recognized for its focus on ease of use, safety, and reliability, making it a competitive entry in the youth ATV market. Its engineering prioritizes a user-friendly experience, incorporating features such as an automatic continuously variable transmission and a robust frame, intended to offer dependable performance for its target demographic. This manual serves as an indispensable resource for maintaining and repairing the KXR 90. It covers a wide array of critical areas, including detailed repair, maintenance, and troubleshooting procedures for engine and electrical systems, as well as general service precautions and recommended practices. The content is structured to assist both professional mechanics, from beginners to advanced technicians, and vehicle owners. By providing in-depth information on disassembly, inspection, rebuilding, and assembly, this manual empowers users to ensure the optimal performance and longevity of their KXR 90 ATV.