1988 KX 250 Manual

The 1988 KX 250 is a high-performance motocross motorcycle featuring a liquid-cooled 249cc two-stroke engine, 43mm conventional forks, Uni-Trak rear suspension system, and advanced chassis design for competitive racing. Below are key sections covering specifications, maintenance procedures, troubleshooting, and technical data for proper operation and service.

Specifications

Technical specifications for the 1988 KX 250 motocross motorcycle.

Component	Specification
Engine Type	Liquid-cooled, single-cylinder two-stroke
Displacement	249cc
Bore x Stroke	67.0 x 70.7mm
Compression Ratio	8.4:1
Carburetor	Keihin PWK 38mm
Ignition	CDI electronic ignition
Transmission	5-speed constant mesh
Front Suspension	43mm conventional telescopic fork
Rear Suspension	Uni-Trak linkage system
Front Brake	Single disc 240mm
Rear Brake	Single disc 240mm
Dry Weight	102 kg (225 lbs)
Fuel Capacity	9.5 liters (2.5 gallons)

Maintenance Schedule

Regular maintenance intervals for optimal performance and longevity.

1. Before each ride: Check fuel level, tire pressure, chain tension, brake operation
2. Every 10 hours: Clean air filter, check spark plug, inspect brakes
3. Every 20 hours: Change transmission oil, check wheel bearings
4. Every 40 hours: Replace spark plug, inspect suspension linkage
5. Every 100 hours: Top end rebuild, inspect crankshaft

WARNING! Always perform maintenance in well-ventilated area. Use proper safety equipment.

Engine Service

Detailed procedures for engine maintenance and repair.

1. Top end rebuild: Remove cylinder head, inspect piston and rings
2. Carburetor adjustment: Main jet 162, pilot jet 52, needle clip position 3
3. Power valve service: Clean and lubricate KIPS system components
4. Cooling system: Check radiator fluid level, inspect hoses for leaks
5. Transmission: Drain and refill with 750ml of 10W-40 motorcycle oil

CAUTION! Engine components get extremely hot. Allow to cool before servicing.

Chassis & Suspension

• Front Forks: 43mm conventional, 300mm travel, adjustable compression/rebound
• Rear Shock: Uni-Trak system, 320mm wheel travel, adjustable preload/compression/rebound
• Frame: Semi-double cradle steel frame
• Wheelbase: 1490mm
• Ground Clearance: 370mm
• Seat Height: 955mm
• Tires: Front 80/100-21, Rear 110/90-19

Electrical System

CDI ignition system with lighting coil for competition use.

Components: CDI unit, ignition coil, spark plug (BR8ES), stator assembly, kill switch.

Battery: Not applicable - magneto powered ignition only. Lighting: Optional lighting kit available. Spark plug gap: 0.6-0.7mm. Ignition timing: Fixed at 1.8mm BTDC.

Fuel System

Keihin PWK 38mm carburetor with recommended fuel mixture.

1. Fuel mixture: 32:1 premium unleaded gasoline with 2-stroke oil
2. Carburetor settings: Main jet 162, pilot jet 52, needle N72C
3. Float height: 16mm
4. Air screw: 1.5 turns out from fully seated

Tip: Always use fresh fuel and proper 2-stroke oil mixture for optimal performance.

Troubleshooting

Common issues and solutions for the 1988 KX 250.

Symptom	Possible Cause	Corrective Action
Hard starting	Fouled spark plug, stale fuel	Replace spark plug BR8ES, drain old fuel
Poor performance	Clogged air filter, incorrect jetting	Clean air filter, check carburetor settings
Transmission noise	Low oil level, worn gears	Check transmission oil, inspect gears
Overheating	Low coolant, clogged radiator	Check coolant level, clean radiator fins
Brake fade	Contaminated pads, air in system	Replace brake pads, bleed brake system

Reset: None required - mechanical systems only.

Torque Specifications

Critical torque values for proper assembly.

Component	Torque Value
Cylinder head nuts	28 Nm (20 ft-lbs)
Spark plug	25 Nm (18 ft-lbs)
Front axle nut	65 Nm (47 ft-lbs)
Rear axle nut	105 Nm (76 ft-lbs)
Engine mount bolts	45 Nm (33 ft-lbs)
Sprocket nuts	65 Nm (47 ft-lbs)

Lubrication Points

Regular lubrication requirements for chassis components.

Chain: Lubricate every ride with chain lube. Steering head bearings: Grease every 40 hours. Swingarm pivot: Grease every 40 hours. Wheel bearings: Inspect and repack every 100 hours. Brake lever pivot: Light oil weekly.

CAUTION! Use only recommended lubricants. Avoid getting lubricants on brake rotors.

Warranty Information

Limited warranty coverage for 1988 KX 250. Original warranty: 30 days for amateur racing use. No warranty for professional racing. For service and parts, contact authorized Kawasaki dealerships. Replacement parts available through Kawasaki Genuine Parts program.