This manual covers 450 EXC, 400 EXC, and 520 SX models produced between 2000 and 2003. These high-performance off-road motorcycles are renowned for their power, agility, and exceptional capability in enduro and motocross applications. Built with a focus on off-road competition and trail riding, models from this era are celebrated for their robust engineering, reliable performance, and winning heritage. This comprehensive workshop service manual provides in-depth information on all aspects of service, maintenance, and repair for these models. It details engine assembly and disassembly, fuel and electrical systems, transmission, chassis components, brakes, and bodywork. The manual also includes essential troubleshooting guides, diagnostic procedures, and technical specifications, making it an indispensable resource for owners and technicians seeking to maintain and optimize their motorcycles. 🏷️ Basic Information Identification Make: KTM Model: 450 EXC, 400 EXC, 520 SX Model Variant Identifier: Dual-sport and Motocross variants Codes Production Years Covered: 2000, 2001, 2002, 2003 👋 Introduction Market Position Category: High-performance off-road motorcycles Target Audience: Enduro and motocross riders, mechanics, technical enthusiasts Competitive Analysis Competitors: Honda CRF series, Yamaha YZ/WR series, Suzuki RM/RMX series, Kawasaki KX/KLX series Key Features Manual Value Proposition: Provides essential technical knowledge for maintaining and repairing sought-after KTM models Vehicle Appeal: Renowned for power, agility, and off-road capability 📋 Manual Details Coverage Areas Primary Coverage: Comprehensive service, maintenance, and repair Secondary Coverage: Troubleshooting, diagnostics, technical specifications Page Count Estimated Page Count: Varies by specific model and year; typically 300-500 pages for full workshop manuals Manual Type Type: Workshop Service Manual Language Language: English Format Format: PDF Download 📖 Manual Coverage Systems Covered Engine: Engine assembly, disassembly, inspection, repair (cylinder head, piston, crankshaft, connecting rod, valve train), lubrication system, cooling system, starting system Fuel System: Carburetor overhaul and adjustment, fuel tank, fuel lines, fuel pump (if applicable) Transmission: Clutch operation, gearbox disassembly and reassembly, gear shift mechanism Electrical System: Ignition system, lighting system, charging system, wiring diagrams, fault finding Chassis: Frame, suspension (forks, rear shock absorber), steering system, wheels and tires Brakes: Front and rear brake systems (hydraulic, caliper, master cylinder, brake lines, brake pads, brake discs) Exhaust System: Exhaust pipe, muffler, mounting Bodywork: Plastic body panels, seat, fuel tank cover, fenders Procedures Included Maintenance: Routine service, oil changes, filter replacement, chain adjustment, lubrication points, valve clearance checks Repair: Engine rebuilds, transmission repairs, suspension overhauls, brake system servicing, electrical component replacement Troubleshooting: Diagnostic flowcharts, common problems and solutions, electrical fault tracing Technical Specifications: Torque values, clearances, fluid capacities, part numbers, engine specifications Technical Depth Depth: In-depth, suitable for professional mechanics and experienced DIY enthusiasts 📊 Manual Specifications File Format File Type: Portable Document Format (PDF) Searchability: Likely text-searchable (depending on original scan quality) Print Quality Printability: Designed for digital viewing and printing of individual pages or sections Binding Type Binding: N/A (Digital Download) Paper Type Paper Quality: N/A (Digital Download) ⚙️ Engine Specifications Primary Engine Engine Type: Four-stroke, single-cylinder (liquid-cooled, SOHC) Displacement 400Exc: Approx. 398cc Displacement 450Exc: Approx. 450cc Displacement 520Sx: Approx. 510-520cc Performance Horsepower Estimate: Varies by model and tuning, generally 45-60+ HP Torque Estimate: Strong mid-range and top-end torque characteristic of KTM off-road engines Fuel System Fuel Delivery: Carburetor (e.g., Keihin PWK series) Fuel Type: Unleaded gasoline (premium recommended) Ignition Ignition System: Digital CDI with variable ignition timing 🔧 Transmission Standard Type: 5-speed or 6-speed manual gearbox (depending on specific model variant) Features Clutch: Hydraulic, multi-plate wet clutch Final Drive: Chain drive 📐 Dimensions Exterior Wheelbase Estimate: Approx. 1470-1485 mm (57.9-58.5 in) Weights Dry Weight Estimate: Approx. 110-125 kg (242-275 lbs) 🛡️ Safety Features Ratings Safety Certification: Off-road vehicles typically not subject to DOT safety ratings in the same way as street vehicles. Active Features Braking System: Powerful hydraulic disc brakes front and rear Passive Features Frame Construction: Chromium-molybdenum steel trellis frame for strength and rigidity 💡 Technology Features Infotainment Features: N/A (basic off-road focused electronics) Driver Assistance Features: N/A Connectivity Features: N/A 🔧 Maintenance Service Intervals Oil Change Interval: Typically every 15-30 hours of riding or annually, depending on usage severity. Specifics in manual. Air Filter Cleaning: Frequent cleaning recommended, especially in dusty conditions; interval varies with environment. Valve Clearance Check: Typically every 30-50 hours of riding. Crucial for engine health. Fluid Specifications Engine Oil Type: High-quality synthetic 4-stroke motorcycle oil, SAE 10W-40 or 15W-50 (refer to manual for exact viscosity based on temperature range). Engine Oil Capacity: Approx. 1.0-1.3 liters (refer to manual for exact capacity with or without filter change). Coolant Type: Ethylene glycol-based antifreeze/coolant mixture (50/50 with distilled water). Brake Fluid Type: DOT 4 hydraulic brake fluid. Known Issues Common Wear Items: Clutch plates, piston rings, valve guides, wheel bearings, chain and sprockets. Potential Failures: Carburetor jetting issues, stator failures, starter motor problems (less common on early models if maintained), shock absorber seal leaks. Maintenance Tips Pre Ride Checks: Tire pressure, chain tension, fluid levels, brake...