This manual covers the LC4 model family, produced from 1998 to 2005, encompassing a range of engine displacements from 400cc to 660cc. The 'Ready to Race' philosophy is evident in this line of performance dual-sport, supermoto, and enduro motorcycles, known for their robust single-cylinder LC4 engines, praised for torque and versatility. The LC4 platform was adapted for diverse disciplines, including adventure, enduro, motocross, and supermoto, demonstrating its adaptable design. This series competed effectively against other performance off-road and street-legal motorcycles of its era, earning a reputation for off-road prowess and durability. This comprehensive workshop repair and service manual provides A-Z coverage for all LC4 engine variants and model variations, including the 400LC4, 620LC4, 640 Adventure, and 660SMC, among many others. It details engine, chassis, electrical systems, fuel, cooling, and exhaust systems, offering step-by-step instructions for routine maintenance, troubleshooting, repair, and rebuilding procedures. With high-quality illustrations and diagrams, this manual is an essential resource for owners, mechanics, and technicians aiming to maintain and repair their LC4 motorcycles to optimal performance standards. 🏷️ Basic Information Identification Make: KTM Model Family: LC4 Engine Displacement Range: 400cc - 660cc Model Years Covered: 1998-2005 Codes Engine Code Prefix: LC4 👋 Introduction Market Position Vehicle Segment: Performance Dual-Sport, Supermoto, and Enduro Motorcycles Brand Philosophy: KTM's 'Ready to Race' philosophy is evident in the LC4 line, demanding precise maintenance and repair for optimal performance. Competitive Analysis Competitors Era: Competed against other European and Japanese performance off-road and street-legal motorcycles of its time. Key Features Engine Type: Robust single-cylinder 'LC4' engine, known for its torque and versatility. Model Diversity: The LC4 platform was adapted for various disciplines: Adventure (640 Adventure), Motocross/Enduro (SXC, EXC variants), and Supermoto (SC, SMC variants). Manual Value Proposition Completeness: 100% complete and intact, ensuring no missing or corrupt pages. Accessibility: Instant download, easy to use, printable for hands-on work. 📋 Manual Details Coverage Areas Primary Coverage: Workshop Repair and Service Model Variations Covered: 400LC4, 400LC4-E, 400SC, 400SX, 400SXC, 540SXC, 620LC4 COMPETITION, 620SC, 620SC SUPERMOTO, 620SX, 625SC, 625SC SUPERMOTO, 625SMC, 625SXC, 625SXC EUR/USA, 640 ADVENTURE-R, 640 DUKE, 640 DUKE AUS/USA, 640 DUKE-E, 640LC4, 640LC4 ADVENTURE, 640LC4 SUPERMOTO, 640LC4-E, 640LC4-E SUPERMOTO, 640 SUPERMOTO, 660RALLY, 660SMC Page Count Estimated Page Count: Highly comprehensive (exact count not provided, but extensive based on sectional listings) Manual Type Type: Workshop Repair Service Manual Language Language: English (presumed based on product description) Format Digital Format: PDF (Downloadable) 📖 Manual Coverage Systems Covered Engine: Engine specifications, diagnostics, repair, rebuild, maintenance for all LC4 engine variants (400cc, 540cc, 600cc, 620cc, 625cc, 640cc, 660cc) Chassis: Chassis components, suspension, steering, frame, wheels, brakes, bodywork Electrical System: Wiring diagrams, ignition system, lighting, charging system, starter system, electronic components Fuel System: Carburetor/fuel injection systems, fuel pump, fuel tank, fuel lines Cooling System: Radiator, coolant, water pump, thermostat (where applicable) Exhaust System: Exhaust pipes, mufflers, emissions controls Procedures Included Maintenance: Routine maintenance, oil changes, filter replacements, chain adjustment, spark plug service, valve clearance checks Troubleshooting: Diagnostic procedures for common and uncommon issues, fault finding guides Repair: Detailed step-by-step repair instructions for all major and minor components, including engine teardown and reassembly Rebuilding Refurbishment: Comprehensive guidance for engine and component rebuilds, refurbishment of worn parts Restoration: Guidance applicable to restoring older models within the specified year range Technical Depth Depth: Professional Technician and Mechanic Level - A-Z coverage Detail Level: Extremely detailed, covering all diagnostic and repair procedures Illustrations: High-quality photos, illustrations, and diagrams included 📊 Manual Specifications File Format Format: PDF Requirements: PDF Reader Compatibility: All Versions of Windows, Mac, and Linux Print Quality Quality: High Quality (printable) Binding Type Binding: Digital Download - No physical binding Paper Type Paper Type: N/A (Digital Format) ⚙️ Engine Specifications Primary Engine Engine Type: Four-stroke, single-cylinder, liquid-cooled (most variants), SOHC/DOHC (depending on specific model) Performance Typical Horsepower Range: Varies significantly by model and year, generally from ~40 HP (400cc) to ~50-60 HP (600cc+ variants). Typical Torque Characteristics: Known for strong mid-range torque, characteristic of larger single-cylinder engines. Fuel System Carburetion: Primarily Mikuni (e.g., TM40, BST40) or Keihin carburetors. Some later models may feature fuel injection. Lubrication Oil Type: High-quality motorcycle-specific 4-stroke engine oil (e.g., JASO MA certified) with appropriate viscosity (e.g., 10W-40, 15W-50 depending on ambient temperature). Maintenance Valve Clearance Intervals: Typically requires checking/adjustment every 5,000-10,000 km (3,000-6,000 miles), specific values detailed in the manual. 🔧 Transmission Standard Transmission Type: 5-speed or 6-speed sequential manual gearbox Optional Optional Transmissions: N/A (standard for the platform) Features Clutch Type: Hydraulically operated multi-plate wet clutch Fluid Specifications Transmission Oil Type: Engine oil is typically used in the shared lubrication system. Refer to manual for exact grade and capacity. 📐 Dimensions Exterior Bike Styles Covered: Adventure, Enduro, Motocross, Supermoto Weights Dry Weight Range: Approximately 130-160 kg (286-352 lbs) depending on the specific model and equipment. 🛡️ Safety Features Ratings Safety Standards: Designed to meet relevant...