This service repair manual covers the Mongoose 250, specifically the KXR250 model variant, from its first generation production years of 2003, 2004, and 2005. Known for its robust engineering and value, the Mongoose series represents a commitment to producing capable sport ATVs. This manual provides comprehensive information designed to assist owners and technicians in understanding, maintaining, and repairing this versatile vehicle, which is engineered for both on-road and off-road enjoyment. This 242-page English-language manual serves as an essential resource for DIY enthusiasts, independent repair shops, and dealerships. It details a wide array of procedures, including engine mechanical work, fuel system servicing, cooling and lubrication system maintenance, electrical system diagnostics, drivetrain upkeep, suspension and steering adjustments, and brake system service. With detailed pictures, part diagrams, and factory-level specifications such as torque values and fluid capacities, this manual is an indispensable tool for ensuring the optimal performance and longevity of your Mongoose 250.