This manual covers the Mongoose 50 / 90 and KXR 50 / 90 All-Terrain Vehicles (ATVs) produced between the years 2004 and 2014. These sport-oriented ATVs are designed for recreational use and offer a balance of performance and affordability, characteristic of a commitment to producing reliable and accessible vehicles. The Mongoose and KXR lines represent a presence in the youth and entry-level ATV market, known for their robust engineering and suitability for various terrains. This comprehensive service repair workshop manual provides in-depth guidance for owners, mechanics, and technicians. It covers essential areas including scheduled maintenance, detailed repair procedures for engine, drivetrain, chassis, and electrical systems, as well as troubleshooting common issues. The manual includes step-by-step instructions, diagnostic charts, and information on special tools, ensuring that all aspects of vehicle upkeep and repair are addressed with clarity and precision.