Segment:
Performance Motocross Motorcycle
Target Audience:
Motocross racers, off-road enthusiasts, mechanics specializing in performance dirt bikes.
Key Competitors:
Honda CR250R, Yamaha YZ250, Suzuki RM250, KTM 250 EXC.
Model Distinction:
Known for strong power delivery, advanced suspension for its era, and competitive motocross performance.
Purpose:
To provide comprehensive technical guidance for maintaining, diagnosing, and repairing the Kawasaki KX250 models from 1992-1993.
Engine:
Complete overhaul, top-end and bottom-end rebuild, cylinder head, piston, connecting rod, crankshaft, seals, gaskets, lubrication system, cooling system (liquid-cooled).
Fuel System:
Carburetor (Keihin PWK), jetting, float adjustment, fuel lines, fuel tank, fuel petcock.
Ignition System:
CDI (Capacitor Discharge Ignition), spark plug, ignition coil, timing, stator, flywheel.
Exhaust System:
Expansion chamber, silencer, mounting hardware, cleaning and repacking.
Drivetrain:
Clutch (wet multi-plate), clutch actuation, transmission (5-speed), gear inspection, shift drum and forks, chain drive, sprocket replacement.
Suspension Front:
Upside-down telescopic forks (Kayaba), internal components, oil levels and types, seal replacement, spring rates, damping adjustments.
Brakes Front:
Hydraulic disc brake, caliper service, master cylinder overhaul, pad replacement, fluid bleeding, rotor inspection.
Wheels And Tires:
Spoke wheel maintenance, rim inspection, tire types and pressures, tube replacement.
Electrical System:
Wiring diagrams, lighting, horn, battery maintenance, fuses, component testing.
Frame And Bodywork:
Chassis inspection, plastics, seat, handlebars, footpegs, general assembly and disassembly.
Rear Suspension:
Uni-Trak single shock system, shock absorber overhaul, linkage maintenance, bearing lubrication, spring preload adjustment.
Rear Brakes:
Hydraulic disc brake, caliper service, master cylinder overhaul, pad replacement, fluid bleeding, rotor inspection.
Maintenance:
Regular service checks, lubrication points, chain adjustment, filter cleaning/replacement, coolant flush, spark plug replacement, air filter service.
Troubleshooting:
Diagnostic procedures for common performance issues, starting problems, electrical faults, clutch slippage, suspension performance.
Repair:
Detailed step-by-step instructions for component removal, disassembly, inspection, repair, reassembly, and adjustment for all major systems.
Rebuilds:
Complete engine rebuild procedures, including crankshaft, connecting rod, and transmission overhauls. Suspension component rebuilds.
Torque Specifications:
Precise torque values for all critical fasteners, bolts, nuts, and screws across all assemblies.
Depth:
Comprehensive, from basic routine maintenance to full engine and suspension overhauls. Designed for skilled mechanics and experienced DIY enthusiasts.
Type:
2-stroke, liquid-cooled
Bore X Stroke:
68.0 x 68.5 mm (typical for this generation)
Compression Ratio:
Approximately 8.4:1 (static, subject to variation)
Cylinder Arrangement:
Single cylinder, forward-canted
Horsepower Est:
Approximately 45-50 HP (at crankshaft, estimated)
Torque Est:
Approximately 28-30 lb-ft (at crankshaft, estimated)
Carburetor Model:
Keihin PWK35
Fuel Type:
Unleaded gasoline (min. 91 octane recommended for optimal performance)
Fuel Mixture:
Pre-mix: 32:1 or 40:1 ratio of gasoline to 2-stroke oil (check manual for specific recommendation)
Transmission Oil Type:
SAE 10W-40 API SG or SH (check manual for exact specification and capacity)
Type:
Constant mesh, 5-speed sequential
Clutch Type:
Wet, multi-plate
Clutch Actuation:
Cable operated
1St Gear:
Refer to manual for specific ratios (e.g., 2.750)
2Nd Gear:
Refer to manual for specific ratios (e.g., 2.000)
3Rd Gear:
Refer to manual for specific ratios (e.g., 1.611)
4Th Gear:
Refer to manual for specific ratios (e.g., 1.333)
5Th Gear:
Refer to manual for specific ratios (e.g., 1.130)
Length:
Approximately 2,165 mm (85.2 in)
Width:
Approximately 820 mm (32.3 in)
Height:
Approximately 1,230 mm (48.4 in)
Wheelbase:
Approximately 1,450 mm (57.1 in)
Ground Clearance:
Approximately 340 mm (13.4 in)
Dry Weight:
Approximately 98 kg (216 lbs)
Curb Weight Est:
Approximately 105-110 kg (231-243 lbs) with fluids
Fuel Tank Capacity:
Approximately 8.0 Liters (2.1 US gal)
Coolant Capacity:
Approximately 0.6 Liters (0.16 US qt)
Oil Change Transmission:
Every 15-20 hours of riding or annually, whichever comes first.
Air Filter Cleaning:
After every few rides, or more frequently in dusty conditions.
Spark Plug Inspection:
Every 10-15 hours of riding.
Chain Lubrication Adjustment:
Every 5-10 hours of riding, or as needed.
Top End Rebuild:
Recommended every 40-60 hours of aggressive riding, or sooner based on performance indicators.
Coolant:
Ethylene glycol-based coolant mixed with distilled water (50/50 ratio) for corrosion protection and freeze resistance.
Fork Oil:
Specific suspension fork oil (e.g., Showa SS-01, Kayaba K-2, or equivalent 5W-10W fork oil). Refer to manual for exact type and volume per fork leg.
Power Valve Sticking:
The powervalve mechanism can accumulate carbon buildup, leading to sticking and reduced performance. Requires periodic cleaning and lubrication as outlined in the manual.
Clutch Wear:
Like all performance 2-strokes, clutch plates can wear relatively quickly under hard use. Regular inspection and adjustment are necessary.
Suspension Seals:
Fork and shock seals are susceptible to wear and leaks, especially with off-road use. Routine inspection and replacement are recommended.
Carburetor Jetting:
Proper carburetor jetting is critical for optimal performance. Changes in altitude, temperature, or modifications require jetting adjustments. The manual provides baseline settings.
Kawasaki Motorsports:
Kawasaki has a long and successful history in motorcycle racing, particularly in motocross and supercross, building a reputation for powerful and competitive machinery.
Kx Series Legacy:
The KX250 is part of Kawasaki's esteemed KX line, which has consistently evolved to meet the demands of professional motocross racing. The early 90s models were significant advancements in performance and suspension technology.
Key Updates 1992-1993:
These model years saw continued refinement, often including improvements in engine tuning, suspension components (such as the Kayaba forks), chassis geometry, and braking systems, building on the success of previous generations.
Manufacturing Location:
Primarily manufactured in Japan.
