This manual covers the 2003 SX, MXC, and EXC series of performance off-road motorcycles, encompassing engine sizes from 250cc to 525cc. These Austrian-manufactured machines are built for demanding motocross, enduro, and dual-sport applications, featuring a robust Chromoly Steel Trellis Frame and powerful single-cylinder, 4-stroke liquid-cooled engines. Renowned for their racing heritage and durable construction, motorcycles of this era are highly regarded for their performance and handling capabilities in competitive off-road environments. This comprehensive Repair Service Manual provides factory-level technical data and procedures essential for the maintenance and repair of your SX/MXC/EXC model. It includes detailed information on engine overhaul, transmission servicing, chassis maintenance, electrical system diagnostics, fuel system adjustments, and braking system upkeep. The manual is designed for both professional technicians and experienced DIY mechanics, offering step-by-step instructions for disassembly, assembly, cleaning, and reinstallation, ensuring the optimal performance and longevity of your motorcycle. 🏷️ Basic Information Identification Make: KTM Model: SX/MXC/EXC Series Year: 2003 Variant Models Covered: 250 SX, 400 SX, 450 SX, 520 SX, 525 SX, 250 MXC, 400 MXC, 450 MXC, 520 MXC, 525 MXC, 250 EXC, 400 EXC, 450 EXC, 520 EXC, 525 EXC Engine Sizes Covered: 250cc, 400cc, 450cc, 520cc, 525cc 👋 Introduction Market Position Market Segment: Performance Off-Road Motorcycles (Motocross, Enduro, Dual-Sport) Competitive Analysis Competitors 2003: Yamaha YZ/WR series, Honda CR/XR series, Suzuki RM/DR series, Kawasaki KX/KLX series Key Features Manual Advantage: Provides factory-level technical data and procedures, often surpassing basic owner's manuals. User Benefit: Enables owners to perform complex maintenance and repairs, saving on dealership labor costs. 📋 Manual Details Coverage Areas Maintenance: Included Troubleshooting: Included Repair Procedures: Included Disassembly: Included Assembly: Included Cleaning Procedures: Included Reinstallation: Included Page Count Estimated Page Count: Approximately 500+ Manual Type Manual Type: Repair Service Manual Classification: Factory Service Manual Equivalent Language Language: English Format File Format: PDF Delivery Method: Instant Download Requirements Software Requirements: Adobe PDF Reader, WinZip Compatibility Operating Systems: All Versions of Windows & Mac 📖 Manual Coverage Systems Covered Engine: Detailed coverage for all listed engine displacements, including top-end, bottom-end, cooling system, lubrication system, and fuel delivery. Transmission: Comprehensive procedures for clutch operation, gear shifting mechanisms, and gearbox servicing. Chassis: Covers frame inspection, suspension setup and repair (front forks, rear shock), steering system, and wheel bearings. Electrical System: Includes wiring diagrams, ignition system diagnostics, lighting, battery maintenance, and starter motor troubleshooting. Fuel System: Details on carburetor removal, cleaning, adjustment, and troubleshooting for all models. Exhaust System: Information on exhaust component inspection and replacement. Brakes: Covers hydraulic brake system maintenance, pad replacement, fluid bleeding, and caliper servicing for both front and rear brakes. Cooling System: Details on radiator, coolant hoses, and water pump maintenance for liquid-cooled models. Procedures Included Engine Overhaul: Complete step-by-step instructions for engine disassembly, inspection of components (pistons, rings, valves, crankshaft), and reassembly. Suspension Servicing: Detailed guidance on fork seal replacement, oil changes, and shock absorber servicing. Carburetor Tuning: Specific instructions for jetting, float height adjustment, and idle speed settings. Electrical Diagnostics: Troubleshooting common electrical faults, testing components, and understanding wiring schematics. Clutch Adjustment: Procedures for clutch lever adjustment and clutch pack inspection/replacement. Wheel And Tire Service: Instructions for tire changing, wheel balancing, and spoke tensioning. Technical Depth Depth: Comprehensive, covering basic maintenance to complete engine and chassis rebuilds. Target Audience Primary Audience: Professional Technicians Secondary Audience: Experienced DIY Mechanics with basic mechanical and electrical knowledge. 📊 Manual Specifications File Format Digital Format: PDF Print Quality Printability: Full Printable Zoom Functionality: YES (Zoom IN/OUT) Binding Type Binding: N/A (Digital Download) Paper Type Paper Type: N/A (Digital Download) ⚙️ Engine Specifications Primary Engine Engine Type: Single-cylinder, 4-stroke (Liquid-cooled) Performance Horsepower Range: Estimated 40-60 HP depending on displacement and tuning. Torque Range: Estimated 35-50 Nm depending on displacement. Fuel System Carburetion: Keihin or Mikuni constant-velocity (CV) carburetors, specific sizes vary by model (e.g., 36mm, 38mm). Valve Train Valve Actuation: DOHC (Double Overhead Camshaft), 4 valves per cylinder. Ignition Ignition System: Digital CDI (Capacitor Discharge Ignition) 🔧 Transmission Standard Transmission Type: 5-speed or 6-speed constant mesh gearbox Optional Clutch Type: Hydraulically operated multi-plate wet clutch Features Gear Ratios: Specific gear ratios are detailed within the manual for each model variant. 📐 Dimensions Exterior Frame Type: Chromoly Steel Trellis Frame Weights Dry Weight: Approximately 105-120 kg (231-265 lbs) depending on model. Fuel Capacity: Approximately 8-10 liters (2.1-2.6 US gallons). 🛡️ Safety Features Ratings Safety Standards: Designed for off-road use; typically not rated by NCAP or similar road safety organizations. Active Features Braking System: Hydraulic disc brakes front and rear (e.g., Brembo calipers often used). Passive Features Frame Integrity: Robust steel frame designed for demanding off-road conditions. 💡 Technology Features Infotainment Features: N/A (Basic off-road motorcycle, no infotainment systems). Driver Assistance Features: N/A (No electronic driver assistance features). Connectivity Features: N/A (No connectivity features). 🔧 Maintenance Service Intervals Oil Change Interval: Typically every 10-15 operating hours or...