This manual covers the 640 LC4 Adventure-R and Duke models produced between 1998 and 2003, featuring the robust LC4 single-cylinder engine. Known for their Austrian engineering and off-road prowess, these versatile motorcycles offer a blend of performance and durability. Whether equipped for adventure touring or street riding, the 640 LC4 platform is celebrated for its capable design and the unique riding experience it provides to dedicated enthusiasts. This comprehensive workshop repair service manual in English provides in-depth guidance for owners and technicians. It details essential maintenance procedures, step-by-step repair instructions, and troubleshooting diagnostics across all major systems, including the engine, drivetrain, chassis, and electrical components. With professional-level detail, clear diagrams, and critical specifications, this manual is an indispensable resource for maintaining the performance and longevity of your 640 LC4. 🏷️ Basic Information Identification Make: KTM Model: 640 LC4 Adventure-R Duke Model Variants: Adventure-R, Duke Generation Production Years: 1998-2003 Codes Engine Code Family: LC4 👋 Introduction Market Position Target Audience: KTM 640 LC4 Adventure-R and Duke owners, independent repair shops, DIY enthusiasts Competitive Analysis Manual Advantage: Provides factory-level information, often more comprehensive than aftermarket alternatives, available digitally for immediate access and convenience Key Features Content Quality: Professional quality, highly detailed, written by manufacturers (KTM) Usability: Easy-to-follow directions, step-by-step procedures, clear diagrams and illustrations, numbered table of contents 📋 Manual Details Coverage Areas Covered Models: KTM 640 LC4 Adventure-R, KTM 640 LC4 Duke (All Variants) Covered Years: 1998, 1999, 2000, 2001, 2002, 2003 Engine Variants: Covers all engine types and configurations for the 640 LC4 platform in these years. Trim Levels: Adventure-R and Duke trim levels covered, detailing differences where applicable. Transmission Types: Covers all transmission types offered for the 640 LC4 during the 1998-2003 model years. Page Count Estimated Pages: Hundreds (Specific count not provided, but described as comprehensive) Manual Type Type: Workshop Repair Service Manual Language Primary Language: English Format Digital Format: PDF Download 📖 Manual Coverage Systems Covered Engine: Top End, Lubrication System, Fuel System, Cooling System Drivetrain: Clutch, Crankshaft, Transmission, Final Drive Chassis: Wheels/Tires, Brakes, Suspension, Steering, Frame Electrical: Complete Electrical System, Wiring Diagrams General Info: Includes general information, specifications, and torque values. Appendix: Includes an appendix with supplementary information. Procedures Included Maintenance: Scheduled Maintenance, Fluid Changes, Filter Replacements, Adjustments Repair: Disassembly, Assembly, Cleaning, Reinstallation, Component Repair Troubleshooting: Diagnostic Procedures, Problem Solving, Electrical Troubleshooting Engine Rebuild: Complete engine disassembly, inspection, and reassembly procedures. Electrical Diagnostics: Detailed troubleshooting for electrical system faults, including wiring diagrams and component testing. Technical Depth Level Of Detail: Professional Technician Level, Including Detailed Diagrams and Substeps Coverage Scope: All Models, Engines, Trim, and Transmission Types within the specified years Specifications: Includes critical specifications, tolerances, and torque values for all components. Illustrations: Abundant diagrams, drawings, and photos to illustrate repair procedures. 📊 Manual Specifications File Format Format: PDF Print Quality Printability: Full Printable Zoom Capability: YES (Zoom In/OUT) Binding Type Binding: N/A (Digital Download) Paper Type Paper Quality: N/A (Digital Download, Print as needed) Delivery Delivery Method: Instant Download Requirements Software Requirements: Adobe PDF Reader, WinZip Compatibility Operating Systems: All Versions of Windows & Mac ⚙️ Engine Specifications Primary Engine Engine Type: LC4 Single-Cylinder, Four-Stroke Engine Displacement: Typically 625cc or 653cc (specifics vary by sub-model and year, manual covers all) Performance Horsepower: Approx. 50-54 HP (Varies by model and year, detailed specs in manual) Torque: Approx. 55-60 Nm (Varies by model and year, detailed specs in manual) Fuel System Fuel Delivery: Carburetor (Mikuni BST/TM series typically), Fuel Injection on later models (covered in manual) Fuel Type: Unleaded Gasoline (Octane rating specified in manual) 🔧 Transmission Standard Transmission Type: 5-Speed Constant Mesh Optional Optional Gearbox: N/A (Standard for these models) Features Clutch Type: Wet Multi-Plate Clutch Final Drive: Chain Drive (O-ring/X-ring type specified) 📐 Dimensions Exterior Overall Length: Varies by model (Adventure-R typically longer for touring) - detailed specs in manual Seat Height: Varies by model, generally tall for adventure riding - detailed specs in manual Weights Dry Weight: Approx. 150-165 kg (Varies by model) - detailed specs in manual Wet Weight: Approx. 170-190 kg (Varies by model) - detailed specs in manual 🛡️ Safety Features Ratings Crash Test Results: N/A (Motorcycle, not subject to standardized automotive crash testing) Active Features Braking System: Hydraulic Disc Brakes (Front and Rear, specifications in manual) Suspension Type: Telescopic Forks (Front), Monoshock (Rear) - adjustable on Adventure-R Passive Features Lighting: Halogen Headlight, LED Tail Light (typical) 💡 Technology Features Infotainment Dashboard: Analog Tachometer, Speedometer, Odometer, Trip Meter, Basic Warning Lights Driver Assistance ABS: Not standard on most models within this range, ABS may have been an option on specific later versions (check manual) Connectivity Usb Charging: Not standard, aftermarket accessory often installed 🔧 Maintenance Service Intervals Oil Change Interval: Typically every 5,000-10,000 km or annually (refer to manual for specific recommendation) Valve Clearance Check: Typically every 10,000-20,000 km (detailed procedure...