Model:
400 EXC, 450 EXC, SMR, SXS
Year:
2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
Common Chassis Codes:
LC4 (general family), specific variations for EXC/SMR/SXS models
Vehicle Segment:
High-performance off-road motorcycles (Enduro, Motocross, Supermoto variants).
Competitors:
Yamaha YZ/WR, Honda CRF/XR, Suzuki RM/DR, Kawasaki KX/KLX, Husqvarna, GasGas.
Engine Philosophy:
Powerful, torquey LC4 single-cylinder engines known for their robustness and off-road capability.
Suspension Performance:
Premium WP suspension components providing exceptional damping and adjustability for demanding terrain.
Handling:
Agile and responsive chassis design optimized for competitive off-road riding.
Engine Mechanical:
Disassembly, assembly, inspection, repair of cylinder head, valves, piston, crankshaft, connecting rod, oil pump, and cooling system.
Fuel System:
Carburetor (Keihin, Mikuni variants), fuel pump, fuel tank, lines, and filtration.
Ignition System:
CDI unit, ignition coil, spark plug, stator, and wiring.
Transmission Drivetrain:
Gearbox disassembly, inspection, repair, clutch operation, chain and sprocket maintenance.
Suspension Front:
Fork disassembly, seal replacement, oil levels, spring rates, damping adjustments (WP USD forks common).
Suspension Rear:
Monoshock (WP PDS or linkage systems), shock absorber service, linkage bearing maintenance.
Brakes Front:
Brake caliper service, master cylinder overhaul, pad replacement, disc inspection, hydraulic lines.
Brakes Rear:
Brake caliper service, master cylinder overhaul, pad replacement, disc inspection, hydraulic lines.
Electrical System:
Wiring diagrams, lighting, starter motor, battery maintenance, charging system, fuse box, switchgear.
Frame Chassis:
Frame inspection, steering head bearing service, swingarm maintenance, subframe.
Bodywork:
Fairing removal and installation, seat, fuel tank mounting, fenders.
Routine Maintenance:
Oil changes, filter replacements, chain lubrication and adjustment, air filter cleaning/replacement, spark plug checks, valve clearance checks.
Troubleshooting:
Diagnostic tables for common starting, running, and electrical issues.
Engine Rebuild:
Complete engine disassembly, component inspection, torque specifications for critical fasteners, reassembly procedures.
Suspension Service:
Front fork seal replacement, rear shock absorber service (where applicable), linkage lubrication.
Brake Service:
Brake bleeding, caliper piston cleaning and lubrication, pad and disc replacement.
Electrical Diagnostics:
Using multimeters to test circuits, identifying faulty components based on symptoms.
Carburetor Tuning:
Adjustment of idle speed, mixture screws, jetting recommendations for altitude and conditions.
Diagnostics Level:
Advanced diagnostics including troubleshooting charts and component testing procedures.
Repair Scope:
Comprehensive repair procedures for major mechanical and electrical components.
Rebuild Procedures:
Detailed instructions for engine and transmission rebuilds.
Technical Drawings:
Includes exploded diagrams and illustrations of components and assemblies.
Engine Type:
Four-stroke, single-cylinder, liquid-cooled (LC4 architecture).
Displacement 400:
Approximately 398cc.
Displacement 450:
Approximately 449cc (exact figures may vary slightly by year and sub-model).
Bore X Stroke 400:
Typical around 95mm x 70.5mm (check specific model year).
Bore X Stroke 450:
Typical around 97mm x 60.8mm (check specific model year).
Horsepower 400:
Estimated 45-55 HP (may vary with tuning and exhaust).
Horsepower 450:
Estimated 50-60 HP (may vary with tuning and exhaust).
Torque:
Strong mid-range torque characteristic of LC4 engines.
Carburetor Type:
Keihin FCR flat-slide or Mikuni VM (depending on year and model variant).
Fuel Type:
Unleaded Gasoline, 91 octane or higher recommended.
Valve Train:
SOHC, 4 valves per cylinder.
Starting System:
Electric Starter (standard on most variants).
Cooling System:
Liquid-cooled.
Transmission Type:
6-speed constant mesh manual gearbox.
Clutch Type:
Wet multi-plate clutch, hydraulically operated.
Gear Ratios:
Specific gear ratios vary by model and intended use (EXC, SXS, SMR); refer to manual for detailed charts.
Final Drive:
Chain drive (e.g., 520 pitch).
Transmission Oil:
SAE 10W-40 or 15W-50 motorcycle-specific engine oil (check manual for exact API rating and specifications, e.g., JASO MA).
Wheelbase:
Varies by model, typically around 1450-1500 mm.
Seat Height:
High, typical for off-road bikes, around 930-970 mm (unladen).
Dry Weight:
Typically in the range of 115-130 kg, depending on model and equipment.
Fuel Tank Capacity:
Around 7-9 liters, with some EXC models having larger optional tanks.
Front Wheel Size:
1.60 x 21 inches (EXC/SXS), 3.50 x 17 inches (SMR).
Rear Wheel Size:
2.15 x 18 inches (EXC/SXS), 5.00 x 17 inches (SMR).
Front Tire Size:
80/100-21 (EXC/SXS), 120/70-17 (SMR).
Rear Tire Size:
100/100-18 or 110/100-18 (EXC/SXS), 160/60-17 (SMR).
Oil Change Interval:
Every 1,000-1,500 km or 6 months, whichever comes first (refer to manual for exact recommendation based on usage).
Air Filter Cleaning:
Frequent cleaning recommended, especially in dusty conditions (e.g., every few rides or 500 km).
Valve Clearance Check:
Initial check at 1,000 km, then every 3,000-5,000 km or annually. Critical for performance and engine longevity.
Chain Tension Adjustment:
Check and adjust as needed, typically every 500-1,000 km.
Coolant:
Ethylene glycol based coolant, mixture of 50% coolant and 50% distilled water.
Brake Fluid:
DOT 4 brake fluid.
Fork Oil:
Specific WP fork oil (e.g., SAE 5 or 7.5), with specific level and volume requirements.
Starter Clutch Wear:
Can be susceptible to wear over time, especially with hard starting or frequent use.
Piston Ring Wear:
As with any high-performance engine, piston ring wear can occur and affect compression and oil consumption.
Water Pump Seal:
The water pump seal is a common maintenance item that may require replacement due to leaks.
Carburetor Jetting Sensitivity:
Carburetors can be sensitive to altitude and temperature changes, requiring periodic jetting adjustments for optimal performance.
Ktm Legacy:
KTM has a strong heritage in off-road racing, particularly Enduro and Motocross, dating back to the 1950s.
Lc4 Development:
The LC4 engine platform has been a cornerstone of KTM's lineup for decades, evolving through various displacements and configurations.
Exc Series:
The EXC line represents KTM's dedicated off-road/enduro models, built for tackling demanding trails and competitions.
Sx Series Legacy:
The SXS models are often race-prepped versions derived from the motocross (SX) line, emphasizing performance for closed-course competition.
Smr Series:
The SMR models are KTM's Supermoto offerings, featuring smaller wheels, street tires, and suspension modifications for asphalt-based racing and high-performance street use.
Manufacturing Location:
Primarily Austria.
