Systems Covered:
General Information, Fuel System, Cooling System, Engine Top End, Engine Right Side, Engine Removal/Installation, Engine Bottom End/Transmission, Wheels/Tires, Final Drive, Brakes, Suspension, Steering, Frame, Electrical System, Appendix
Page Count Estimate:
Estimated 300-500 pages (typical for this era's comprehensive service manuals)
Manual Type:
Factory Service Repair Manual
Requirements:
Adobe PDF Reader
Engine Internal Components:
Detailed coverage of piston, rings, cylinder, connecting rod, crankshaft, bearings, cylinder head, valves, camshafts, timing chain, and all associated seals and gaskets.
Fuel Delivery:
Carburetor (Keihin PJ series commonly) disassembly, cleaning, adjustment, jetting specifications, float level, and fuel pump/filter (if applicable).
Cooling System:
Radiator, hoses, water pump, thermostat, coolant types and capacities, bleeding procedures, and temperature sensor diagnostics.
Lubrication System:
Oil pump, oil passages, oil filter, and oil type recommendations.
Ignition System:
CDI unit, ignition coil, spark plug type and gap, stator, and timing specifications.
Transmission And Clutch:
Gearbox inspection, maintenance, and repair; clutch assembly, plates, springs, and hydraulic actuation system (if applicable).
Suspension Front:
Fork disassembly, seal replacement, oil type and level, damping adjustments, spring rates, and steering bearing service.
Suspension Rear:
Monoshock absorber service, linkage maintenance, pivot bearing inspection and lubrication, and rear shock adjustments.
Braking System:
Front and rear brake caliper service, master cylinder overhaul, brake pad replacement, brake fluid type and bleeding procedures, rotor specifications.
Wheel And Tire:
Spoke tensioning, rim maintenance, hub bearing service, tire pressure recommendations, and wheel alignment procedures.
Final Drive:
Chain and sprocket inspection, lubrication, adjustment, and replacement recommendations.
Electrical System:
Wiring diagrams, component identification, troubleshooting guides for lighting, ignition, and accessory circuits.
Frame And Bodywork:
Frame inspection, swingarm pivot maintenance, footpeg mounts, and body panel removal/installation.
Routine Maintenance:
Oil changes, filter replacements, chain adjustments, spark plug checks, air filter cleaning/replacement, brake pad inspection.
Troubleshooting:
Diagnostic procedures for common starting issues, engine performance problems, electrical faults, and suspension issues.
Component Overhaul:
Step-by-step instructions for complete disassembly, cleaning, inspection, and reassembly of major engine and chassis components.
Technical Specifications:
Torque values for all fasteners, engine tolerances, fluid capacities, jetting specifications, valve clearances, ignition timing.
Wiring Diagrams:
Detailed, clear wiring schematics for the entire electrical system, including color coding and component locations.
Special Tools:
Identification of any specialized tools required for specific maintenance or repair procedures.
Depth Of Coverage:
Comprehensive, covering everything from basic maintenance to complete engine rebuilds and advanced diagnostics.
Engine Type:
Liquid-cooled, 2-stroke, single-cylinder (Note: The 'F' designation typically implies 4-stroke. This manual covers both if there were variations, but 1994-2007 KX250 models were predominantly 2-stroke. The KX250F as a 4-stroke model began later. The description might be slightly ambiguous, but the coverage areas point to a comprehensive mechanical manual for the KX250 lineage which included 2-strokes during this period. For clarity, a 2004+ KX250F is a 4-stroke.)
Bore X Stroke:
Varies by year; e.g., 66.4 mm x 72 mm for 2004 KX250F
Displacement:
249 cc (typically)
Horsepower:
Varies by year and tuning; typically in the 45-50 HP range for this era's performance motocross bikes.
Torque:
Varies by year and tuning; typically in the 27-30 lb-ft range.
Carburetor Type:
Typically Keihin PJ series, single flat-slide carburetor
Fuel Grade:
Premium Unleaded Gasoline (91 octane or higher)
Engine Oil Change:
Every 5-10 hours of riding or as specified in the manual; critical for 2-stroke pre-mix or 4-stroke engine oil.
Air Filter Cleaning:
Every 2-5 hours of riding, depending on conditions, or before each race.
Chain Lubrication Adjustment:
Every ride; inspect and adjust slack as needed.
Spark Plug Check:
Every 10-15 hours of riding; replace as needed.
Suspension Service:
Fork oil and seal replacement every 20-30 hours of riding; shock service periodically.
Engine Oil Type:
For 2-stroke models: High-quality 2-stroke synthetic or semi-synthetic oil mixed with gasoline at the recommended ratio (e.g., 32:1 or 40:1). For 4-stroke models: SAE 10W-40 API SG or higher, JASO MA certified motorcycle engine oil.
Coolant Type:
Permanent type anti-freeze coolant (ethylene glycol based) mixed with distilled water (50/50 ratio).
Brake Fluid Type:
DOT 4 hydraulic brake fluid.
Kx250 2Stroke Common:
Carburetor jetting issues, power valve adjustments, crankshaft seal leaks, reed valve wear, ignition coil failures.
Kx250F 4Stroke Common:
Cam chain tensioner noise, valve clearance issues, clutch wear, carburetor tuning sensitivity, exhaust valve cleaning.
Suspension Wear:
Fork seal leaks and worn bushings are common with heavy use.