Category:
High-performance motocross competition motorcycle.
Target Audience:
Professional motocross racers, amateur competitors, and serious off-road enthusiasts.
Key Competitors:
Yamaha YZ450F, Honda CRF450R, Suzuki RM-Z450, Kawasaki KX450F.
Engine Layout:
Single-cylinder, four-stroke, liquid-cooled.
Suspension Brand:
WP Suspension (often).
Frame Type:
Chromoly steel, perimeter or backbone frame.
Primary Coverage:
Complete service, repair, and maintenance for the KTM 450 SX Racing 2000-2003 models.
Secondary Coverage:
Troubleshooting, diagnostics, specifications, wiring diagrams, and torque values.
Estimated Page Count:
Varies by edition, typically 300-500+ pages for a comprehensive workshop manual.
Type:
Workshop Repair Service Manual
Engine:
Complete teardown, reassembly, tuning, carburetor service, piston, cylinder, valve train, crankshaft, and lubrication system.
Transmission:
Clutch operation, gearbox inspection, gear replacement, shift mechanism, and lubrication.
Fuel System:
Carburetor adjustment and overhaul (e.g., Keihin PWK), fuel pump (if applicable), fuel tank, and fuel lines.
Ignition System:
CDI unit, spark plug specifications, stator, and troubleshooting ignition faults.
Cooling System:
Radiator maintenance, coolant specifications, hose inspection, and water pump service.
Suspension:
Front fork (e.g., WP USD) service, rear shock absorber overhaul, spring rates, damping adjustments, and seal replacement.
Brakes:
Hydraulic brake system service (front and rear), caliper maintenance, master cylinder, brake fluid specifications, pad replacement, and bleeding procedures.
Electrical System:
Wiring diagrams, lighting system, battery maintenance, fuses, and troubleshooting electrical faults.
Chassis And Frame:
Frame inspection, steering head bearing service, footpeg mounting, and general chassis components.
Wheels And Tires:
Spoke tensioning, wheel bearing maintenance, tire pressure recommendations, and mounting/dismounting tires.
Maintenance:
Routine inspections, oil changes, filter replacements, chain adjustment, and general servicing.
Troubleshooting:
Step-by-step guides for diagnosing and resolving common operational problems.
Repair:
Detailed instructions for component replacement and repair across all major vehicle systems.
Overhaul:
Complete engine, transmission, and suspension unit rebuild procedures.
Adjustment:
Carburetor tuning, suspension sag, chain slack, and clutch lever play.
Torque Specifications:
Precise torque values for all critical fasteners.
Depth:
Comprehensive, covering from basic maintenance to full engine and component rebuilds.
Diagnostics:
Advanced diagnostic procedures for identifying faults in engine, electrical, and mechanical systems.
Special Tools:
Identification and usage of specialized tools required for specific procedures.
Displacement:
Approximately 449cc.
Bore X Stroke:
Specifics vary slightly by year but generally around 95mm x 63.4mm.
Valvetrain:
SOHC (Single Overhead Camshaft), 4 valves.
Compression Ratio:
Typically in the range of 11.5:1 to 12.5:1.
Horsepower:
Estimated 50-55 HP at peak.
Torque:
Estimated 40-45 Nm at peak.
Carburetor Type:
Keihin PWK 36mm (common specification for this era).
Fuel Type:
Unleaded gasoline, octane rating 91 or higher.
Oil Type:
JASO MA certified 4-stroke motorcycle engine oil, SAE 10W-40 or 10W-50 (refer to manual for exact viscosity based on temperature).
Oil Capacity:
Approximately 0.6-0.8 liters (dry fill, check manual for specific amount for oil change).
Wheelbase:
Varies slightly by year, typically around 1470-1480 mm (57.9-58.3 inches).
Seat Height:
Approximately 950-960 mm (37.4-37.8 inches).
Ground Clearance:
Approximately 350-360 mm (13.8-14.2 inches).
Dry Weight:
Approximately 105-110 kg (231-243 lbs).
Wet Weight:
Varies based on fluids, estimated 115-120 kg (254-265 lbs).
Safety Rating:
Not applicable as per typical automotive safety rating bodies (e.g., NHTSA, Euro NCAP) for competition off-road vehicles.
Brake System:
Hydraulic disc brakes front and rear for powerful stopping.
Suspension Control:
Adjustable suspension for optimized handling and stability.
Frame Integrity:
Robust chassis construction designed to withstand rigorous competition.
Ergonomics:
Designed for rider control and confidence during aggressive riding.
Engine Oil Change:
Every 10-15 hours of riding or as specified in the manual for optimal performance.
Air Filter Cleaning:
After every few rides, or more frequently in dusty conditions.
Spark Plug Inspection:
Every 20-30 hours of riding.
Chain Lubrication And Adjustment:
After every wash or ride, and check tension regularly.
Valve Clearance Check:
Every 30-50 hours of riding, or as per manual recommendations.
Brake Fluid:
DOT 4 hydraulic brake fluid.
Coolant:
Ethylene glycol-based antifreeze and distilled water mixture (50/50 ratio recommended), or specific KTM coolant.
Carburetor Fouling:
Can occur with improper fuel or prolonged storage; requires regular cleaning and jetting checks.
Clutch Wear:
Normal wear item, especially under aggressive riding; requires periodic inspection and replacement.
Suspension Seal Leaks:
Front fork or rear shock seal leaks can occur with heavy use; require seal replacement.
Engine Top End Wear:
Piston, rings, and cylinder can show wear over extended high-hour usage; requires rebuild.
Origins:
KTM, founded in Austria in 1934, is renowned for its off-road racing prowess, particularly in motocross and rally raid.
Development Focus:
The 450 SX Racing models from this era represented KTM's commitment to developing competitive four-stroke motocross machines, building on their success in two-stroke categories.
Key Advancements:
Introduction and refinement of powerful four-stroke engines, advanced WP suspension, and improved chassis geometry for handling.
Manufacturing Location:
Austria.
Significance:
These models were pivotal in establishing KTM as a major player in the four-stroke motocross market, directly competing with Japanese manufacturers.
