This manual covers 250 SX, 525 SX, 250 MXC, 525 MXC, 250 EXC, and 525 EXC models manufactured between 2000 and 2003. These robust off-road motorcycles, featuring the renowned LC4 engine family, were built for demanding motocross, cross-country, and enduro applications. Known for their performance-oriented design and Austrian engineering, these motorcycles have a strong legacy in motorsports, offering riders powerful engines with substantial torque, advanced suspension systems, and durable chassis built for challenging terrain. This comprehensive service and repair manual focuses on engine repair and service, providing detailed instructions for disassembly, reassembly, component servicing, and troubleshooting of all major engine systems. It includes information on the clutch, gearbox, lubrication, cooling, fuel, and ignition systems, as well as internal engine components. Written at a professional technician level, this manual is an essential resource for owners and independent repair shops, enabling accurate maintenance, efficient repairs, and a thorough understanding of these specialized off-road vehicles. 🏷️ Basic Information Identification Make: KTM Model: 250 SX, 525 SX, 250 MXC, 525 MXC, 250 EXC, 525 EXC Model Variants: SX (Motocross), MXC (Cross-Country), EXC (Enduro) Generation Year Range: 2000-2003 Codes Engine Codes: LC4 series (specific codes may vary by exact model and year, e.g., 250 EXC-R, 525 EXC-R) 👋 Introduction Market Position Target Audience: KTM owners and independent repair shops specializing in off-road motorcycles. Competitive Analysis Value Proposition: Provides dealership-level repair knowledge for the specific KTM models, enabling users to perform complex engine work and troubleshooting efficiently, saving costs associated with professional labor. Key Features Manual Benefits: Comprehensive engine repair instructions, detailed diagrams, troubleshooting guides, technical specifications, and periodic maintenance schedules for a DIY or professional approach. 📋 Manual Details Coverage Areas Manual Scope: Engine Repair and Service Page Count Estimated Page Count: Comprehensive (Exact page count not specified, but described as 'comprehensive') Manual Type Type: Service/Repair Manual (Supplementary) Language Language: English Format Format: PDF Download 📖 Manual Coverage Systems Covered Engine Systems: Engine disassembly, reassembly, component servicing, lubrication system, cooling system (if applicable to specific models), fuel system (carburetor tuning/rebuild), ignition system, internal engine components (pistons, rings, rods, crankshaft, valves, camshafts, bearings), clutch, gearbox (internal components), starting system. Procedures Included Repair Procedures: Engine removal and refitting, complete engine disassembly, individual component servicing (e.g., piston replacement, valve adjustment, bearing replacement), engine assembly, troubleshooting common engine issues, basic maintenance procedures. Technical Depth Depth Of Information: Professional Technician Level - Covers detailed diagnostic procedures, overhaul instructions, and technical specifications equivalent to those used by dealership technicians. 📊 Manual Specifications File Format File Type: PDF Print Quality Printability: Printable 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 (LC4 engine family) Displacement 250: Approximately 250cc (e.g., 250 EXC, 250 SX) Displacement 525: Approximately 525cc (e.g., 525 EXC, 525 SX) Performance Horsepower Range: Varies significantly by model and year, typically ranging from ~30-40 HP for 250cc to ~45-55 HP for 525cc. Torque Characteristics: LC4 engines are known for strong mid-range and low-end torque, especially the larger displacement variants, suitable for off-road applications. Fuel System Carburetor Type: Typically Keihin (e.g., Keihin FCR models common in this era), with specific sizes varying by engine size and model variant. Fuel Type Recommendation: Unleaded gasoline, octane rating typically 90 or higher (refer to manual for specific recommendations). 🔧 Transmission Standard Transmission Type: Constant-mesh, 5 or 6-speed sequential manual transmission (number of gears can vary by specific model variant and year within this range). Optional Optional Transmissions: N/A (Manual transmission is standard for these off-road models). Features Clutch Type: Hydraulically operated multi-plate wet clutch. Transmission Fluid Type: Dedicated gearbox oil (e.g., Motorex Gear Oil or equivalent meeting KTM specifications, often SAE 80W/90 or similar). 📐 Dimensions Exterior Dimensions: Varies by model variant (SX, MXC, EXC) and year. Typically designed for off-road maneuverability. Weights Dry Weight: Varies by model, typically in the range of 105-125 kg (approx. 230-275 lbs) depending on engine size and equipment. 🛡️ Safety Features Ratings Safety Compliance: Designed for off-road competition and recreational use; compliance with road safety standards is model-specific and may require modifications for street legality in some regions. Active Features Braking System: Hydraulic disc brakes front and rear. Typically Brembo components used in this era. Suspension System: High-performance upside-down telescopic forks (e.g., WP Suspension) and monoshock rear suspension with adjustable damping and pre-load. Passive Features Frame Type: Chromium-molybdenum steel central tube frame. 💡 Technology Features Infotainment Display System: Basic digital or analog instrument cluster displaying speed, RPM, odometer, trip meter, and basic warning lights. No advanced infotainment systems. Driver Assistance Electronic Aids: Limited to basic ignition and carburetor tuning. No electronic rider aids like traction control or ABS on these models. Connectivity Connectivity Features: N/A 🔧 Maintenance Service Intervals Oil Change Interval: Typically every 10-20 operating hours or as specified in the manual for race conditions;...