🏷️ Basic Information

Make:

KTM

Model:

LC4

Sub Model:

400-660 Series

Applicable Model Years:

1998, 1999, 2000, 2001, 2002, 2003

Engine Family Code:

LC4 (Liquid-Cooled Four-stroke)

👋 Introduction

Motorcycle Segment:

Dual-sport, Enduro, Supermoto

Competitors Era:

Honda XR series, Yamaha WR/XT series, Suzuki DR series, Kawasaki KLR/KLX series, Husqvarna TE series.

Lc4 Engine Characteristics:

Known for its robust, torque-rich single-cylinder design, reliability, and versatility across different riding disciplines. Often characterized by its distinctive LC4 rumble.

Manual Value Proposition:

Provides riders and technicians with the official, in-depth knowledge required to maintain, diagnose, and repair these capable Austrian motorcycles, ensuring longevity and optimal performance.

📋 Manual Details

Primary Coverage:

KTM 400 LC4, KTM 525 LC4, KTM 540 LC4, KTM 560 LC4, KTM 600 LC4, KTM 620 LC4, KTM 625 LC4, KTM 640 LC4, KTM 650 LC4, KTM 660 LC4

Engine Variants Covered:

Various single-cylinder displacements within the 400cc to 660cc range (specific engine codes for each displacement should be cross-referenced within the manual)

Estimated Page Count:

Likely extensive, typically 300+ pages for comprehensive factory manuals covering multiple variants.

Manual Type:

Official Factory Service / Repair / Workshop Manual

Language:

English (presumed, as standard for official factory manuals targeting international markets)

File Format:

PDF

📖 Manual Coverage

Engine Mechanical:

Engine disassembly, assembly, cylinder head, valve train (camshafts, valves, springs, guides, seals), pistons, rings, connecting rods, crankshaft, balancing shafts, oil pump, oil system, lubrication, cooling system (radiator, fan, oil cooler), timing systems (gears, chains, belts), engine mounts.

Fuel System:

Carburetor (maintenance, adjustment, troubleshooting, jetting, diaphragm replacement), fuel pump, fuel lines, fuel filters, intake manifolds, airbox, air filter replacement.

Ignition System:

Ignition coils, spark plugs, spark plug wires, CDI unit, timing adjustments, sensors, troubleshooting.

Transmission And Drivetrain:

Gearbox inspection, disassembly, assembly, gear ratios, shift mechanism, clutch (friction plates, steel plates, springs, pressure plate, seals, hydraulic actuation if applicable), chain and sprocket maintenance, rear hub, wheel bearings.

Brakes:

Brake caliper service, piston replacement, seal kits, brake pads, brake shoes, rotors, brake lines (hydraulic), master cylinders, slave cylinders, bleeding procedures, fluid specifications.

Suspension:

Front fork (fork seals, oil changes, spring replacement, damping adjustments), rear shock absorber (rebuilding, oil changes, gas charging if applicable), linkage systems, wheel bearings.

Electrical System:

Wiring diagrams, component identification, charging system (stator, rectifier/regulator), battery maintenance, starter motor, lighting (headlights, taillights, turn signals), switches, fuses, sensor wiring.

Chassis And Bodywork:

Frame inspection, steering head bearings, swingarm bearings, body panel removal and installation, seat, fuel tank, fenders, exhaust system (muffler, downpipe, gaskets), heat shields.

Routine Maintenance:

Oil and filter changes, air filter cleaning/replacement, spark plug replacement, chain adjustment, brake pad inspection, tire pressure checks, coolant level checks.

Diagnostic Procedures:

Troubleshooting guides for common issues, electrical system diagnostics, engine performance analysis, carburetor tuning.

Major Repairs:

Engine rebuilds, transmission overhaul, suspension servicing, brake system overhauls, electrical component replacement.

Technical Specifications:

Torque values for all fasteners, engine clearances (valve lash, piston-to-wall), fluid capacities, electrical system specifications, dimensional data.

Special Tools:

Identification and usage of specialized tools required for specific procedures (e.g., flywheel puller, clutch holding tool).

Depth Of Coverage:

Comprehensive, covering everything from basic adjustments to complete engine and chassis teardowns and rebuilds. Factory-level detail.

📊 Manual Specifications

File Format:

PDF

Printability:

Yes

Zoom Capability:

Yes

Manual Quality:

Factory

Binding Type:

N/A (Digital Download)

Paper Type:

N/A (Digital Download)

⚙️ Engine Specifications

Engine Type:

Liquid-cooled, four-stroke, single-cylinder

Bore Stroke Variants:

Varies significantly across 400cc to 660cc models. Examples: 400cc (approx. 84x72mm), 640cc (approx. 101x80mm). Exact figures for each displacement are detailed in the manual.

Valve Train:

SOHC (Single Overhead Camshaft) with 4 valves, actuated by rocker arms or direct tappets depending on specific model iteration.

Horsepower Range:

Approximately 30-55 HP depending on displacement and tuning. Manual will detail specific output for each variant.

Torque Characteristics:

Strong low-end and mid-range torque, characteristic of larger displacement single-cylinder engines.

Carburetor Type:

Primarily Mikuni or Keihin flat-slide carburetors (e.g., VM series, CV carbs). Specific models and sizes (e.g., 36mm, 38mm, 40mm) vary by engine displacement.

Fuel Delivery:

Gravity feed from fuel tank to carburetor, or sometimes electric fuel pump for later models or specific variants.

Oil Capacity Approx:

Typically 1.5 - 2.0 liters. Manual will specify exact capacity for each model.

Oil Type Recommendation:

Synthetic or semi-synthetic motorcycle oil with appropriate viscosity grade (e.g., 10W-40, 15W-50) and JASO MA certification. Manual will provide precise specifications.

🔧 Transmission

Transmission Type:

5-speed or 6-speed constant mesh manual gearbox.

Optional Features:

Not typically offered with automatic transmissions in this era for LC4 models.

Clutch Type:

Wet multi-plate clutch, often hydraulically actuated.

Gear Ratios:

Specific gear ratios for each model and transmission variant are detailed in the manual.

📐 Dimensions

Seat Height Approx:

High, typically 35-37 inches, varying by model and suspension setup.

Ground Clearance Approx:

Generous, often 10-12 inches or more, suitable for off-road use.

Dry Weight Approx:

Around 300-350 lbs (135-160 kg), depending on model and equipment.

🛡️ Safety Features

Safety Ratings:

Not applicable in the same way as cars; focus is on rider protection and mechanical integrity.

Active Safety:

Effective braking systems (often Brembo or Grimeca), responsive suspension, and rider control geometry.

Passive Safety:

Sturdy frame construction, durable components, appropriate lighting for visibility.

💡 Technology Features

Infotainment System:

Basic; typically limited to analog or simple digital dashboards displaying speed, RPM, odometer, trip meter, and basic warning lights.

Driver Assistance Features:

None.

Connectivity Options:

None.

🔧 Maintenance

Oil Change Interval:

Typically every 3,000-5,000 km (1,800-3,000 miles) or annually. Manual provides precise intervals.

Valve Adjustment Interval:

Often around 6,000-10,000 km (3,700-6,200 miles). Critical for maintaining performance and preventing damage. Manual details procedure and specific intervals.

Spark Plug Replacement:

Recommended at 6,000-12,000 km (3,700-7,500 miles), depending on plug type. Manual specifies recommended plugs and intervals.

Coolant Type:

Ethylene glycol-based antifreeze coolant, mixed with distilled water in a 50/50 ratio. Manual specifies type and capacity.

Brake Fluid Type:

DOT 4 or DOT 5.1 hydraulic brake fluid. Manual specifies exact type and bleeding procedure.

Common Wear Items:

Clutch plates (especially with aggressive use), valve guides, countershaft seals, wheel bearings, fork seals, carburetor diaphragms.

Performance Considerations:

Carburetor tuning can be sensitive to altitude and temperature. Regular valve clearance checks are crucial for optimal performance and engine longevity.

Comprehensive Schedule:

The manual will contain a detailed, mileage-based and time-based maintenance schedule for all major components and systems.

📚 Vehicle History

Ktm Heritage:

KTM, an Austrian manufacturer, has a strong heritage in off-road racing and performance motorcycles, known for its 'Ready to Race' philosophy.

Lc4 Development:

The LC4 engine platform has a long and successful lineage, evolving from earlier enduro and rally bikes into versatile dual-sport and supermoto machines. The 400-660 series represents a significant phase of this development.

Production Period:

The LC4 platform was in production for many years, with the 400-660 models being prominent in the late 90s and early 2000s.

🏆 Awards & Recognition

Brand Awards:

KTM frequently wins accolades in off-road racing disciplines, contributing to its reputation for performance and durability.

Model Reputation:

The LC4 series is generally well-regarded for its power, torque, and ability to handle both on-road commuting and off-road exploration, earning a loyal following among riders.