This manual covers the KTM SX, MXC, and EXC models from the year 2000, equipped with engine variants including 250cc, 400cc, 450cc, 520cc, and 525cc. These motorcycles are engineered for demanding off-road competition, including Motocross (SX), Off-road Competition (MXC), and Enduro (EXC) disciplines. KTM's legacy in off-road racing is evident in these models, which feature a chromium-molybdenum steel trellis frame for strength and rigidity, and hydraulic disc brakes for superior stopping power in challenging conditions. The 2000 era models represented a significant advancement in KTM's dirt bike technology, focusing on refined power delivery and enhanced reliability. This comprehensive English-language repair service manual provides detailed, step-by-step instructions for maintenance and repair procedures. It covers all major systems, including the engine, transmission, chassis, electrical system, brakes, and fuel system, with specific guidance on component disassembly, repair, and reassembly. The manual includes critical technical specifications, torque values, fluid capacities, and diagnostic information to assist professional technicians and knowledgeable DIY enthusiasts. Its purpose is to enable informed decision-making for upkeep and repairs, imparting factory-level knowledge for optimal performance and longevity of your KTM motorcycle.