Sub Models:
250 SX, 250 EXC, 400 EXC, 450 SX, 450 EXC, 520 EXC, 525 SX, 525 EXC
Production Years Covered:
2000, 2001, 2002, 2003, 2004, 2005, 2006
Chassis Codes General:
Varies by specific model and year (e.g., LC4-based for larger displacements, SX/EXC specific platforms)
Engine Mechanics:
Engine disassembly, assembly, inspection, repair, and overhaul procedures for all covered engine variants.
Fuel System:
Carburetor (Keihin, Mikuni variations) and fuel injection system diagnostics, adjustment, and repair; fuel pump, filter, and tank service.
Ignition System:
CDI, electronic ignition components, spark plug specifications, troubleshooting, and stator/coil testing.
Cooling System:
Radiator, fan, coolant hoses, thermostat, and water pump service and troubleshooting.
Exhaust System:
Exhaust pipe, muffler, and heat shield inspection and replacement.
Transmission And Drivetrain:
Clutch operation, disassembly, and adjustment; gearbox inspection, repair, and overhaul; chain and sprocket wear and replacement.
Suspension Front:
Upside-down telescopic fork service (KYB, WP variations), oil changes, seal replacement, damping adjustments.
Suspension Rear:
Monoshock rear suspension service, linkage maintenance, shock absorber overhaul and adjustment.
Brakes Front:
Hydraulic disc brake system service, caliper overhaul, pad replacement, rotor inspection, master cylinder maintenance.
Brakes Rear:
Hydraulic disc brake system service, caliper overhaul, pad replacement, rotor inspection, master cylinder maintenance.
Wheels And Tires:
Spoke wheel maintenance, hub service, bearing replacement, tire mounting and balancing, wheel alignment.
Electrical System:
Wiring diagrams, battery maintenance, lighting, starter motor, charging system (stator, regulator/rectifier) testing and repair.
Chassis And Frame:
Frame inspection, steering head bearing service, subframe maintenance.
Bodywork And Plastics:
Fairing, seat, fuel tank cover, and fender removal, installation, and repair.
Routine Maintenance:
Oil and filter changes, air filter cleaning/replacement, chain adjustment, spark plug replacement, brake fluid flush, coolant checks.
Troubleshooting:
Diagnostic flowcharts and procedures for common operational issues and component failures.
Engine Rebuild:
Detailed steps for top-end (piston, cylinder, valve train) and bottom-end (crankshaft, bearings) overhaul.
Suspension Rebuild:
Fork seal replacement, damper rod service, shock absorber seal head replacement and nitrogen charging.
Electrical Diagnostics:
Testing of charging system, ignition, lighting, and starting circuits using multimeters and specific diagnostic tools.
Clutch Service:
Clutch plate replacement, basket inspection, and hydraulic clutch bleeding.
Brake System Overhaul:
Caliper piston seal replacement, master cylinder rebuild, brake line bleeding.
Carburetor Tuning And Rebuild:
Jetting specifications, float level adjustment, and complete carburetor disassembly/reassembly.
Depth Level:
Comprehensive: Covers everything from basic rider maintenance to full engine, transmission, and suspension rebuilds.
Diagnostic Capability:
Advanced: Includes detailed troubleshooting guides and component testing procedures, often with electrical schematics.
Special Tools Required:
Mentions specific KTM or commonly used motorcycle service tools for specialized tasks (e.g., flywheel puller, suspension tools).
Engine Type 250:
Single-cylinder, 4-stroke (various configurations across years, some SOHC, some DOHC).
Engine Type 400/450/520/525:
Single-cylinder, 4-stroke, typically SOHC (LC4 engine architecture dominant in this range).
Displacement Range:
Approximately 250cc to 525cc.
Starter System:
Electric start and/or kick start (varies by model and year).
Horsepower Range:
Estimated 40-60+ HP, depending on displacement and tuning (exact figures vary).
Torque Range:
Significant torque, particularly in larger displacement models, optimized for off-road traction.
Fuel Delivery 250:
Primarily carbureted (e.g., Keihin PWK, Mikuni TM) for early models in this range, some later 250s might have had FI.
Fuel Delivery 400-525:
Primarily carbureted (Keihin FCR series common on LC4 models) for this period.
Oil Change Interval:
Typically 15-30 engine hours or annually, depending on usage intensity. Manual will specify exact intervals.
Air Filter Cleaning:
Frequent cleaning recommended, especially in dusty conditions (e.g., every 5-10 hours).
Valve Clearance Check:
Critical periodic maintenance, often around 50-100 engine hours. Manual will provide exact specs and intervals.
Engine Oil:
Specific viscosity grades (e.g., Motorex SAE 10W/50 or 15W/50, or equivalent JASO MA certified oil). Manual will specify precise type and quantity.
Coolant:
High-quality, ethylene glycol-based coolant with anti-corrosion additives. Manual will specify type and mix ratio.
Brake Fluid:
DOT 4 or DOT 5.1 hydraulic brake fluid. Manual will specify exact type.
Fork Oil:
Specific weight and viscosity for front forks (e.g., WP 4W or 5W suspension fluid). Manual will detail exact type and level.
Common Wear Items:
Clutch plates, brake pads, wheel bearings, steering head bearings, chain and sprockets, fork seals, exhaust packing (if applicable).
Lc4 Engine Considerations:
LC4 engines of this era can be robust but require diligent maintenance. Specific issues might include cam chain tensioner wear or potential overheating if cooling system is neglected. Manual will guide on inspection points.