Segment:
High-performance motocross racing motorcycle, targeting competitive riders.
Competitors 1992 1993:
Suzuki RM250, Yamaha YZ250, Honda CR250R.
Engine Type:
Liquid-cooled, 2-stroke, single-cylinder engine.
Suspension Front:
Conventional telescopic forks, often with adjustable compression and rebound damping.
Suspension Rear:
Monoshock rear suspension with linkage, typically featuring adjustable preload, compression, and rebound damping.
Brakes:
Hydraulic disc brakes front and rear.
Performance Focus:
Aggressive power delivery, lightweight chassis, and advanced suspension for motocross racing.
Engine:
Full engine disassembly, inspection, repair, and reassembly. Includes top-end (cylinder, piston, rings, head), bottom-end (crankshaft, connecting rod, bearings), cooling system, lubrication system, and exhaust system.
Transmission:
Gearbox internal inspection, maintenance, and repair, including clutch operation, shift mechanism, and gear ratios.
Suspension:
Front fork (telescopic) disassembly, servicing, and adjustment. Rear shock absorber (monoshock) removal, inspection, and service procedures. Includes spring rates, damping adjustments, and oil levels.
Brakes:
Front and rear hydraulic disc brake systems, including caliper overhaul, master cylinder service, brake line replacement, and bleeding procedures.
Electrical:
Ignition system troubleshooting and repair, lighting circuits, charging system (if applicable to a 2-stroke off-road), wiring diagrams, and component testing.
Fuel System:
Carburetor disassembly, cleaning, adjustment, and jetting. Fuel tank and petcock inspection and service.
Cooling System:
Radiator inspection, coolant flush and refill, hose replacement, and thermostat (if applicable) service.
Frame And Bodywork:
Chassis inspection, swingarm and linkage maintenance, handlebar and lever replacement, plastics and seat removal/installation.
Maintenance:
Routine service, oil changes (gearbox oil), filter cleaning/replacement, chain adjustment, spark plug replacement, air filter cleaning.
Troubleshooting:
Systematic diagnostic procedures for common performance issues, starting problems, and operational faults.
Repair:
Detailed step-by-step instructions for component repair and replacement, including torque specifications.
Overhaul:
Complete rebuild procedures for major components such as the engine, carburetor, and brake calipers.
Adjustment:
Carburetor tuning, suspension settings, chain slack, and clutch lever free play.
Depth:
Comprehensive, suitable for professional technicians and experienced DIY mechanics. Covers detailed internal component specifications and service procedures.
Engine Type:
Liquid-cooled, 2-stroke, single-cylinder
Displacement:
249 cc (15.2 cu in)
Bore X Stroke:
67.4 mm x 70.0 mm (2.65 in x 2.76 in)
Compression Ratio:
Approx. 8.7:1 (varies slightly by year/model)
Ignition:
CDI (Capacitor Discharge Ignition)
Air Intake:
Reed valve induction
Power Valve:
Kawasaki Integrated Power Valve System (KIPS)
Horsepower Estimated:
Approx. 45-50 HP (at crankshaft, estimated for the era)
Torque Estimated:
Approx. 28-30 lb-ft (at crankshaft, estimated for the era)
Carburetor:
Keihin PWK39 (39mm) flat slide carburetor
Fuel Type:
Unleaded gasoline (minimum 91 octane recommended for optimal performance and engine longevity)
Fuel Mix:
50:1 ratio of premium unleaded gasoline to high-quality 2-stroke synthetic oil (e.g., JASO FD certified).
Clutch:
Wet, multi-disc, cable-actuated
Options:
None (standard configuration for motocross)
Gear Ratios:
Detailed gear ratios provided within the manual for each gear (e.g., 1st: 2.500, 2nd: 1.750, 3rd: 1.333, 4th: 1.091, 5th: 0.958, 6th: 0.870).
Final Drive:
O-ring sealed chain drive (typically 13T front sprocket, 48T rear sprocket in stock configuration, but varies with use case).
Length:
Approx. 2185 mm (86.0 in)
Width:
Approx. 820 mm (32.3 in)
Height:
Approx. 1260 mm (49.6 in)
Wheelbase:
Approx. 1475 mm (58.1 in)
Ground Clearance:
Approx. 340 mm (13.4 in)
Seat Height:
Approx. 955 mm (37.6 in)
Dry Weight:
Approx. 99 kg (218.3 lbs)
Wet Weight:
Approx. 107 kg (235.9 lbs) (with all fluids)
Fuel Capacity:
8.0 L (2.1 US gal)
Oil Capacity Transmission:
0.7 L (0.74 US qt) of SAE 10W-30 API SE or SF engine oil.
Safety Certification:
Not applicable for off-road competition motorcycles in this era. Focus is on rider protection through proper gear and safe riding practices.
Braking System:
Powerful hydraulic disc brakes front and rear for controlled stopping power.
Suspension Control:
Adjustable suspension allows tuning for stability and rider control in various terrain conditions.
Chassis Design:
Strong, lightweight frame providing stability and predictable handling.
Tire Grip:
Designed for aggressive off-road tire fitment to maximize traction.
Air Filter Cleaning:
After every few rides, or more frequently in dusty conditions. Specific cleaning and re-oiling procedure detailed in manual.
Spark Plug Replacement:
As needed, check plug condition during routine maintenance. Manual will specify recommended plug type (e.g., NGK BR8EG).
Chain Lubrication Adjustment:
Lubricate chain after every ride or as needed. Adjust slack according to manual specifications (typically 20-30mm of play).
Gearbox Oil Change:
Recommended every 10-20 hours of riding, or as per manual's mileage equivalent. Check level more frequently.
Top End Rebuild:
Recommended between 20-40 hours of aggressive use, or based on compression readings. Manual details piston, ring, and cylinder inspection criteria.
Suspension Service:
Fork oil change every 15-30 hours. Full fork and shock service every 40-60 hours, or as per manual recommendations.
Transmission Oil:
SAE 10W-30, API SE or SF classification. Kawasaki recommends its own brand of 2-stroke transmission oil.
Coolant:
Permanent type antifreeze coolant, typically a 50/50 mix of distilled water and ethylene glycol-based coolant. Manual specifies exact capacity and type.
Fork Oil:
Specific weight and volume per fork leg, as detailed in the manual. Typically around 5W or 10W fork oil.
Engine Wear 2Stroke:
Like all 2-strokes, piston rings and cylinder wear are common with high mileage/hours, especially with improper maintenance or poor quality oil.
Carburetor Jetting:
Carburetor jetting may need adjustment based on altitude, temperature, and modifications to the exhaust or air intake. The manual provides baseline settings.
Power Valve Sticking:
The KIPS power valve can accumulate carbon deposits and may require cleaning and lubrication to ensure proper operation and prevent sticking.
Clutch Wear:
Clutch plates can wear out over time, especially with aggressive riding. The manual provides specifications for clutch plate thickness and free play.
Suspension Seals:
Fork seals and shock seals can degrade over time, leading to oil leaks and loss of damping performance. Regular inspection and replacement are recommended.
Kawasaki Motocross:
Kawasaki has a long and successful history in motocross racing, with the KX line being a dominant force for decades.
Kx250 Evolution Early 90S:
The early 1990s KX250 models were known for their powerful engines, strong chassis, and increasingly sophisticated suspension, making them competitive in AMA Supercross and Motocross.
Key Upgrades 92 93:
Specific upgrades between 1992 and 1993 typically involved minor engine tuning, suspension refinements, and chassis tweaks for improved handling and performance.
Manufacturing Location:
Primarily manufactured in Japan by Kawasaki Heavy Industries.
Production Years Kx250:
The KX250 model has a long production run, spanning from the late 1970s to the mid-2000s, with continuous evolution in technology and performance.
Racing Success:
Kawasaki KX models have consistently achieved top results in professional motocross and supercross championships worldwide, earning a reputation for performance and reliability in competition.
Magazine Reviews Era:
Contemporary reviews from motorcycle publications of the era often praised the KX250 for its potent engine, capable suspension, and agile handling, positioning it as a strong contender in its class.
Emissions Certification:
Not applicable for competition off-road motorcycles in this period. Designed for closed-course use.
