Category:
High-performance off-road motorcycles (Enduro/Motocross).
Target Audience:
Owners, mechanics, and enthusiasts of KTM 400 EXC, 450 EXC, and 520 SX models from the specified years.
Competitors:
During the 2000-2003 period, key competitors included Yamaha WR series, Honda CRF/XR series, Suzuki DR-Z series, and Kawasaki KX/KDX series motorcycles.
Manual Value Proposition:
Provides comprehensive, authoritative guidance for maintaining and repairing these specialized off-road KTM models, empowering owners to perform tasks themselves or understand complex repairs.
Vehicle Attributes:
Known for their powerful engines, advanced suspension, and robust off-road capability, making them popular for competition and serious trail riding.
Engine:
Detailed disassembly, assembly, troubleshooting, and overhaul for all engine variants (400cc, 450cc, 520cc) including valve clearance, piston, cylinder, crankshaft, and lubrication system.
Transmission:
Complete coverage of gearbox disassembly, assembly, inspection, and repair, including clutch operation and adjustment.
Fuel System:
Carburetor (likely Keihin or Mikuni) tuning, cleaning, rebuilding, and troubleshooting; fuel tank and petcock maintenance.
Ignition System:
CDI ignition system diagnostics, troubleshooting, and component testing (stator, coil, spark plug).
Cooling System:
Radiator, coolant hoses, water pump, and thermostat maintenance and inspection.
Suspension:
Front fork (e.g., WP USD) and rear shock absorber service, including oil changes, seal replacement, and adjustments.
Brakes:
Front and rear hydraulic brake system service, including caliper overhaul, pad replacement, fluid bleeding, and master cylinder inspection.
Electrical System:
Wiring diagrams, battery maintenance, lighting system, and troubleshooting of electrical faults.
Chassis And Frame:
Frame inspection, steering head bearing service, and general chassis component maintenance.
Wheels And Tires:
Wheel bearing inspection and replacement, spoke tensioning, and tire pressure recommendations.
Exhaust System:
Exhaust pipe and muffler inspection and maintenance.
Scheduled Maintenance:
Oil changes, filter replacements, chain adjustment and lubrication, air filter cleaning/replacement, spark plug inspection, valve clearance checks.
Disassembly And Assembly:
Complete step-by-step instructions for engine, transmission, suspension, and braking system components.
Troubleshooting:
Diagnostic procedures for common problems related to starting, running, electrical systems, and performance.
Repair And Overhaul:
Detailed instructions for rebuilding carburetors, engines, transmissions, and suspension components.
Wiring Diagrams:
Comprehensive electrical schematics for all systems.
Specifications And Torques:
Essential torque values, clearances, fluid types, and capacities for all components.
Depth:
Comprehensive. Covers everything from basic maintenance to full engine and component rebuilds, including advanced diagnostics and troubleshooting.
Engine Type:
Four-stroke, single-cylinder, liquid-cooled.
Bore X Stroke:
Varies by model (e.g., 400 EXC: ~86 x 70 mm, 450 EXC: ~95 x 63.4 mm, 520 SX: ~95 x 72 mm - specific values available in manual).
Displacement:
400cc, 450cc, 520cc.
Horsepower:
Varies by model and tuning, typically in the range of 40-55 HP (exact figures available in manual).
Torque:
Significant torque delivery optimized for off-road conditions (specific figures available in manual).
Carburetor Type:
Keihin FCR (Flat CR) or Mikuni VM series (specific model dependent, manual will confirm).
Fuel Type:
Unleaded gasoline, 91-98 RON (Octane Rating) recommended.
Oil Type:
High-quality synthetic 4-stroke motorcycle oil (e.g., Motorex, Castrol) with JASO MA rating. Specific viscosity (e.g., 10W-40, 15W-50) and capacity detailed in manual.
Engine Identification:
Engine serial numbers are typically located on the crankcase (specific location detailed in manual).
Type:
Constant mesh, sequential manual gearbox.
Number Of Gears:
Typically 5 or 6 speeds, depending on the specific model variant (manual will specify).
Optional Gearboxes:
N/A (These models came with a standard gearbox).
Clutch Type:
Wet, multi-plate clutch, hydraulically operated.
Gear Ratios:
Specific gear ratios for each model are provided in the manual.
Transmission Oil Type:
Usually the same as engine oil, meeting specific viscosity and JASO MA standards. Manual will specify capacity and type.
Length:
Varies by model, typically around 2100-2250 mm.
Width:
Varies by model, typically around 800-850 mm (excluding handlebars).
Height:
Varies by model, typically around 1250-1350 mm.
Dry Weight:
Approximately 105-115 kg (unladen, without fuel). Exact figures available in manual.
Wet Weight:
Approximately 120-130 kg (with all fluids and standard equipment). Manual will provide specifics.
Fuel Capacity:
Typically around 7-9 liters (1.8-2.4 gallons). Manual will list exact capacity.
Ground Clearance:
Generous, designed for off-road use (specific figures available in manual).
Seat Height:
Typically around 950-980 mm. Manual will provide precise measurement.
Safety Ratings:
As these are off-road competition motorcycles, formal crash safety ratings like those for road vehicles are not applicable or provided.
Braking System:
Powerful hydraulic disc brakes (Brembo or equivalent) front and rear, offering excellent stopping power.
Suspension Control:
High-quality, adjustable suspension components (WP) provide stability and control over varied terrain.
Frame Construction:
Robust steel or chromoly trellis frame designed for durability and rigidity in demanding off-road conditions.
Ergonomics:
Designed for rider control and comfort during aggressive riding.
Engine Oil Change:
Every 15-20 hours of riding or annually. Manual will specify exact interval and conditions.
Air Filter Cleaning:
Recommended after every few rides, especially in dusty conditions. Detailed cleaning procedure in manual.
Valve Clearance Check:
Typically every 30-50 hours of riding. Crucial for performance and engine longevity; manual provides specific tolerances.
Chain Lubrication And Adjustment:
Regularly, depending on riding conditions. Manual outlines correct tension and lubrication schedule.
Spark Plug Inspection:
Every 20-30 hours of riding. Manual provides correct gap and inspection criteria.
Fork Oil Type:
Specific suspension fluid (e.g., WP Suspension Fluid, Maxima, Motorex) with defined viscosity (e.g., 5W, 7.5W). Manual will specify type and level.
Brake Fluid Type:
DOT 4 or DOT 5.1 hydraulic brake fluid (manual will confirm exact type).
Common Wear Items:
Clutch plates, piston rings, valve guides, wheel bearings, fork seals, chain and sprockets are common wear items for high-performance off-road bikes of this era.
Engine Considerations:
Valve seat wear and camshaft wear can occur with high mileage. Proper valve adjustments and oil changes are critical. Manual will detail inspection procedures.
Carburetor Tuning:
Can be sensitive to altitude and temperature changes; proper jetting and idle adjustment are key. Manual provides base settings and troubleshooting.
Brand Origin:
KTM is an Austrian manufacturer renowned for its off-road racing heritage and dominance in disciplines like motocross and enduro.
Exc Series Evolution:
The EXC line represents KTM's commitment to enduro racing, evolving from earlier models with a focus on performance, reliability, and lightweight design. These models marked a significant step in KTM's four-stroke off-road technology.
Sx Series Evolution:
The SX line is KTM's motocross-focused range. The 520 SX was a powerful machine within this lineage, often serving as a platform for competitive racing.
Manufacturing Location:
Austria (primarily).
Production Period:
2000-2003 models are part of a generation that saw continuous refinement of KTM's four-stroke off-road offerings.
Motorsport Success:
KTM models from this era achieved significant success in various off-road racing disciplines, including enduro and desert racing, underscoring their performance and reliability.
Industry Acclaim:
Praised for their powerful engines, capable chassis, and competitive performance against European and Japanese rivals.
Owner Satisfaction:
Generally high among dedicated off-road riders who value performance and the unique KTM riding experience.
Emissions Certification:
Models were designed to meet emissions standards for their respective markets at the time of sale. Manual may contain relevant certification information.
