1988 KX 125 Manual

The 1988 KX 125 is a high-performance motocross motorcycle featuring a liquid-cooled 2-stroke 125cc engine, 6-speed transmission, Uni-Trak rear suspension system, front and rear disc brakes, and Kawasaki's advanced chassis design. This manual covers maintenance procedures, specifications, troubleshooting, and repair guidelines for optimal performance and longevity.

Features at a Glance

Key components: Liquid-cooled 2-stroke engine, 6-speed transmission, Uni-Trak rear suspension, front and rear disc brakes, aluminum swingarm.

Feature	Description
Engine Type	Liquid-cooled, 2-stroke single cylinder
Displacement	124cc
Transmission	6-speed constant mesh
Front Suspension	Air-adjustable telescopic fork
Rear Suspension	Uni-Trak system with adjustable preload
Front Brake	Hydraulic disc
Rear Brake	Hydraulic disc
Fuel Capacity	2.1 gallons (8 liters)
Dry Weight	194 lbs (88 kg)
Seat Height	36.2 inches (920 mm)

Installation & Assembly

Unpack and inspect contents. Assemble components following safety procedures.

1. Handlebar installation: Mount handlebars to triple clamp, torque to specification.
2. Front wheel installation: Install wheel with axle and secure with pinch bolts.
3. Controls installation: Mount clutch and brake levers, adjust free play.
4. Fuel system: Add recommended 32:1 fuel/oil mixture.

WARNING! Motorcycle is heavy; use proper lifting techniques. Ensure all fasteners are torqued to specification.

First-Time Setup

Complete pre-ride inspection and adjustments before operation.

1. Check fluid levels: Engine oil, coolant, brake fluid.
2. Tire pressure: Set to recommended PSI (front 12-15, rear 10-12).
3. Suspension adjustment: Set sag and damping for rider weight.
4. Control adjustments: Set lever positions and throttle free play.
5. Break-in procedure: Follow recommended break-in schedule.

CAUTION! Always wear proper protective gear. Perform safety check before each ride.

Specifications

• Engine: 124cc liquid-cooled 2-stroke single
• Bore x Stroke: 54.0 x 54.5 mm
• Compression Ratio: 8.4:1
• Carburetor: Keihin PWK 34mm
• Ignition: CDI electronic
• Transmission: 6-speed, wet multi-disc clutch
• Final Drive: Chain 520-112 links
• Frame: Semi-double cradle, high-tensile steel
• Wheelbase: 57.5 inches (1460 mm)
• Ground Clearance: 13.4 inches (340 mm)

Controls and Settings

Familiarize yourself with all controls before operation.

Handlebar Controls: Throttle, front brake lever, clutch lever, kill switch, choke lever.

Foot Controls: Gear shift lever, rear brake pedal.

Adjustable Settings: Suspension preload and damping, brake lever position, clutch lever position, handlebar position, chain tension.

Maintenance Procedures

Regular maintenance schedule for optimal performance.

1. Pre-ride inspection: Check tires, controls, fluids, chain tension.
2. After-ride cleaning: Wash motorcycle, lubricate chain, check for damage.
3. Weekly maintenance: Clean air filter, check spoke tension, inspect brakes.
4. Monthly maintenance: Change transmission oil, check valve clearance.
5. Seasonal maintenance: Overhaul suspension, replace brake fluid.

Tip: Keep detailed maintenance records for warranty and resale value.

Engine Service

2-stroke engine maintenance and troubleshooting procedures.

1. Spark plug: Check and replace regularly, gap to 0.6-0.7mm.
2. Carburetor adjustment: Main jet, pilot jet, air screw settings.
3. Top end rebuild: Piston and ring replacement intervals.
4. Crankcase inspection: Check for air leaks and bearing wear.
5. Cooling system: Check radiator, hoses, and coolant level.
6. Exhaust system: Clean power valve, repack silencer.

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

Suspension Adjustment

Uni-Trak rear suspension and front fork adjustment procedures.

Front Fork: Air pressure adjustment, compression damping, rebound damping.

Rear Shock: Spring preload, compression damping, rebound damping, high/low speed adjustment.

Sag Measurement: Set race sag to 95-100mm for optimal handling.

Care & Cleaning

Proper cleaning and storage procedures to maintain appearance and function.

Use mild soap and water for cleaning. Avoid high-pressure spray on bearings and seals. Lubricate chain after washing. Store in dry, covered area. Use fuel stabilizer for long-term storage.

CAUTION! Do not use harsh chemicals that may damage plastics and finishes.

Regulatory Information

Manufactured by Kawasaki Heavy Industries, Ltd. Meets applicable EPA and CARB emissions standards for off-road motorcycles. Intended for closed-course competition use only. Not legal for street use. Always obey local riding area regulations and wear approved safety equipment.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Hard starting	Fouled plug, stale fuel	Replace spark plug; drain old fuel; check compression.
Poor performance	Clogged air filter, jetting	Clean air filter; adjust carburetor jetting.
Transmission issues	Low oil, worn clutch	Check oil level; inspect clutch plates; adjust cable.
Brake problems	Air in lines, worn pads	Bleed brakes; replace pads; check rotor.
Suspension bottoming	Low oil, wrong spring	Check oil level; adjust preload; service suspension.

Technical Support: Contact authorized Kawasaki dealer for complex repairs.

Parts: Use genuine Kawasaki parts for optimal performance and reliability.