🏷️ Basic Information

Make:

KTM

Model:

640 LC4

Model Variant:

LC4, Adventure, Duke II, 660 SMC

Model Years Covered:

Likely covering a range of years within the 640's production (early 2000s to mid-2000s, exact range requires further manual analysis)

Engine Code Series:

LC4

👋 Introduction

Target Audience:

KTM 640 LC4, LC4 Adventure, LC4 Duke II, and 660 SMC owners and independent repair shops.

Value Proposition:

Provides essential technical information for maintaining and repairing these popular KTM models, saving owners money on dealer services and ensuring proper maintenance.

Illustrations:

Includes numerous pictures and diagrams for visual guidance during disassembly, assembly, and repair.

Completeness:

Covers a wide range of tasks from basic maintenance to complete engine and transmission rebuilds, making it a comprehensive resource.

Convenience:

Instant digital download, printable pages for practical workshop use.

📋 Manual Details

Scope:

Complete service and repair for KTM 640 LC4, LC4 Adventure, LC4 Duke II, and 660 SMC models. Includes owner's manuals for specific variants.

Total Pages:

Approximately 420 pages (206 for 640 manual + 53 for LC4 owner's + 59 for LC4 Adventure owner's + 50 for Duke II owner's + 55 for 660 SMC owner's)

Primary Type:

Service Repair Manual

Secondary Types:

Owner's Manuals (for LC4, LC4 Adventure, Duke II, 660 SMC)

Primary Language:

German

File Format:

PDF

Compatibility:

Windows, macOS

📖 Manual Coverage

Engine:

Complete engine tear-down and rebuild, including cylinder head, piston, crankshaft, lubrication system, cooling system (if applicable to specific model variants), and valve train.

Fuel System:

Carburetor overhaul, jetting, fuel pump (if applicable), fuel tank, lines, and filters.

Ignition System:

Ignition coil, spark plug, CDI unit, and related wiring.

Transmission:

Gearbox disassembly, inspection, and assembly; clutch operation and service; shifting mechanisms.

Chassis:

Frame inspection and repair, subframe, steering head bearings, and triple clamps.

Suspension:

Front fork (e.g., WP) service, seal replacement, oil levels, and rear shock absorber maintenance and adjustments.

Brakes:

Front and rear brake system maintenance, caliper service, master cylinder overhaul, brake pad replacement, bleeding procedures, and brake line inspection.

Electrical System:

Wiring diagrams, battery, starter motor, lighting, instrumentation, fuses, relays, and troubleshooting electrical faults.

Bodywork:

Fairings, fenders, seat, fuel tank mounting, and associated hardware.

Maintenance:

Regular service checks, oil changes, filter replacements, chain adjustment, lubrication, and general upkeep.

Troubleshooting:

Diagnostic steps for common performance issues, starting problems, electrical faults, and operational anomalies.

Repair:

Detailed instructions for component replacement and repair across all major vehicle systems.

Rebuild:

Complete tear-down and reassembly procedures for engines and transmissions.

Torque Specifications:

Precise torque values for all critical fasteners and components.

Level Of Detail:

Comprehensive, suitable for both novice mechanics and experienced technicians. Covers everything from basic fluid checks to full engine rebuilds.

📊 Manual Specifications

PDF Quality:

Digital Adobe PDF, offering clarity and readability. High-quality images and diagrams.

Searchability:

Likely searchable text within the PDF (dependent on original scanning/creation quality).

Printability:

All pages are printable, allowing users to create physical copies for workshop use.

Digital Format:

Not Applicable (Digital Download)

Digital Format:

Not Applicable (Digital Download)

⚙️ Engine Specifications

Engine Type:

Single-cylinder, four-stroke (LC4 designation refers to Liquid Cooling 4-stroke)

Displacement:

Typically 625cc to 660cc depending on the specific variant (e.g., 640 LC4, 660 SMC).

Bore X Stroke:

Varies by specific model year and displacement, but common for 640 to be around 100mm x 81.2mm.

Cooling System:

Liquid-cooled

Horsepower:

Typically in the range of 45-55 HP, depending on the specific model and tuning. The 660 SMC would likely have higher output.

Torque:

Expect peak torque figures around 50-60 Nm, specific values would be in the manual.

Carburetion:

Primarily Keihin CV carbs (e.g., CVK40 or similar), later models might have fuel injection. Manual will detail specific carburetors and settings.

Fuel Type:

Unleaded gasoline (RON 95 or higher recommended, check manual for specific octane)

Oil Type:

High-quality motorcycle-specific 4-stroke engine oil, often with JASO MA certification. Manual will specify viscosity (e.g., 10W-40, 15W-50) and API rating.

Oil Capacity:

Typically around 1.8-2.2 liters, including filter. Manual will provide exact figures.

🔧 Transmission

Type:

5-speed manual gearbox

Clutch:

Wet multi-plate clutch

Transmission Oil Type:

Often shares engine oil, but manual will specify if separate or if a specific grade is recommended.

📐 Dimensions

Wheelbase:

Varies by model (e.g., Adventure models generally have longer wheelbases for stability). Exact figures will be in the manual.

Dry Weight:

KTM 640 models typically range from approximately 140-160 kg (dry weight), with the Adventure model potentially being slightly heavier.

Wet Weight:

Will be higher than dry weight due to fluids. Manual will specify.

🛡️ Safety Features

Crash Test Results:

Not applicable (Motorcycle)

Braking System:

Hydraulic disc brakes front and rear, often with Brembo components.

Frame Construction:

Chromoly steel trellis frame for strength and rigidity.

Lighting:

Headlight, taillight, brake light, turn signals.

💡 Technology Features

Instrumentation:

Basic analog or digital instrumentation including speedometer, tachometer (often), odometer, trip meter, and indicator lights. Manual will detail their functions.

ABS:

ABS was an optional feature on some later 640 models. Manual will indicate if ABS is present and its operation.

Diagnostic Ports:

May have basic diagnostic connectors for checking certain parameters, though full OBD-II style diagnostics are unlikely for this era.

🔧 Maintenance

Oil Change Interval:

Typically every 5,000-7,500 km or annually. Manual will specify exact intervals and conditions.

Air Filter Cleaning:

Every 5,000 km or as needed depending on riding conditions. Manual will detail inspection and cleaning procedure.

Spark Plug Replacement:

Typically every 10,000-15,000 km. Manual will specify plug type and gap.

Valve Clearance Check:

Crucial maintenance item for single-cylinder engines. Intervals typically around 10,000-15,000 km. Manual will provide exact checks and adjustment procedures.

Coolant Type:

Ethylene glycol-based antifreeze/coolant, typically a 50/50 mix with distilled water. Manual will specify type and capacity.

Brake Fluid Type:

DOT 4 or DOT 5.1 brake fluid. Manual will specify correct type and change interval.

Common Wear Items:

Clutch plates, valve stem seals, wheel bearings, and brake pads are common wear items that may require regular replacement.

Potential Problems:

Oil leaks from the engine casing or rocker cover are sometimes reported, and carburetor performance can be sensitive to altitude and tuning. Manual will provide troubleshooting for these.

Carburetor Cleaning And Tuning:

Regular cleaning and proper jetting are key for optimal performance and reliability of the carbureted models.

📚 Vehicle History

Ktm Legacy:

KTM is renowned for its off-road and performance motorcycles, with a strong racing heritage. The LC4 engine platform has been a cornerstone for many of their street and dual-sport bikes.

Lc4 Development:

The LC4 platform evolved from earlier single-cylinder KTM designs, becoming a robust and powerful engine used across various models including the Duke, Adventure, and Enduro lines, with the 640 being a significant iteration.

Production Era:

The KTM 640 series was primarily produced in the late 1990s and through the 2000s, with specific model years varying.

🏆 Awards & Recognition

Model Reputation:

The KTM LC4 platform is respected for its torque, versatility (especially the Adventure variant), and robust construction, making it a favorite among riders seeking a capable single-cylinder machine.