1990 Kawasaki KDX 125SR Service Manual (P/N 99924-1130-01)

This 211-page PDF contains the Kawasaki Heavy Industries Motorcycle Service Manual for the 1990 Kawasaki KDX125SR, Part No. 99924-1130-01, First Edition (1), dated April 30, 1990. Its model-application table identifies KDX125-A1 beginning with frame DX125A-000001 and KDX125-B1 beginning with frame DX125B-000001. The repair material is suited to technicians and experienced owners who already understand basic motorcycle service and have access to the specified pullers, drivers, gauges, and electrical test equipment.

• Variant coverage: Identifies KDX125-A1 and KDX125-B1 from their beginning frame numbers and flags U.K., French, Greek, Italian, Norwegian, Swiss, South African, Swedish, and West German specification differences.
• Fuel, induction, and oil injection: Covers Keihin PE28 carburetor removal, disassembly, service fuel-level checks, reed-valve inspection, throttle and oil-pump cable synchronization, oil-pump bleeding, and delivery testing.
• Engine and transmission repair: Details engine removal, compression testing, cylinder and piston service, KIPS exhaust-valve inspection, clutch and primary-drive work, crankcase splitting, crankshaft alignment, and six-speed transmission disassembly and reassembly.
• Chassis service: Includes wheel, tire, and hub-bearing work; chain and sprocket inspection; front and rear caliper and master-cylinder service; brake bleeding; front-fork disassembly; Uni-Trak linkage; swingarm; and steering-stem repairs.
• Electrical diagnosis: Provides a complete motorcycle wiring diagram, charging and ignition tests, flywheel magneto, regulator/rectifier, coil, pickup and exciter checks, lighting and meter service, switch and sensor inspection, and oil-level warning circuit troubleshooting.
• Factory reference data: Combines cable, wire, and hose routing views, exploded assemblies, a periodic maintenance chart, torque tables, fluid and capacity data, wear and service limits, electrical test values, and symptom-based troubleshooting.

Two-Stroke Engine and Drivetrain Repair

The engine chapters are organized around the 124 mL, liquid-cooled, crankcase-reed two-stroke with a Keihin PE28 carburetor, CDI ignition, Kawasaki Superlube oil injection, wet multidisc clutch, six-speed transmission, and chain final drive. Top-end coverage includes cylinder compression testing; cylinder-head, cylinder, piston, ring, and pin service; inspection limits; and KIPS exhaust-valve removal, installation, inspection, and operating checks. Expansion-chamber and silencer work is also included.

The right-side engine chapter handles clutch free play and cable service, clutch plates, springs, hub and housing inspection, the exhaust advancer, external shift mechanism, primary gear, kickstarter, and oil-pump idle gear. Bottom-end repair goes through engine removal, crankcase splitting and assembly, crankshaft and connecting-rod work, big-end inspection, runout and alignment, plus transmission-shaft, shift-drum, shift-fork, gear-dog, and bearing inspection. The related assembly notes, service limits, and special-tool callouts are provided with the procedures.

Cooling, Chassis, and Electrical Diagnosis

The cooling chapter documents coolant replacement, system pressure testing, radiator-cap and filler-neck checks, water-pump shaft and impeller service, mechanical- and oil-seal replacement, thermostat testing, hose routing, and water-temperature sensor inspection. The water-pump section flags a specific assembly trap: blocking the seal drainage passage can force coolant past the oil seal and into the transmission oil.

Chassis repair covers wheels, spokes, rims, tires, hub bearings, the speedometer drive, chain and sprockets, front and rear disc brakes, calipers, master cylinders, brake-fluid replacement and bleeding, forks, Uni-Trak linkage, swingarm, and steering stem. The brake chapter separately warns that mixing fluid types or brands can lower the boiling point, reduce braking effectiveness, and damage rubber components.

Factory Tools, Diagrams, and Scope

Named Kawasaki tools include the Compression Gauge 57001-221 and adapter 57001-1139, Crankcase Splitting Tool Assembly 57001-1098, Crankshaft Jig 57001-1174, Fork Oil Seal Driver 57001-1219, Flywheel Puller 57001-252, and Hand Tester 57001-983. Electrical procedures cover magneto output, charging coils, regulator/rectifier circuits, ignition coil, pickup and exciter coils, IC igniter, lighting, meter, switches, sensors, battery, and engine-oil-level warning diagnosis.

Useful visual references include the full motorcycle Wiring Diagram, dedicated Cable, Wire, and Hose Routing layouts, the Cooling System flow view, Exhaust Valve Operation illustrations, the Ignition System circuit, and the Engine Oil Level Warning System Wiring Diagram. Chapter-opening exploded views support repair and reassembly throughout the engine and chassis sections.

The rear-shock section covers spring-preload adjustment and shock removal and installation, but not an internal shock rebuild. The exploded views show component relationships and assembly order; this is not an illustrated parts-number catalog or a frame-straightening guide. Motorcycle repair carries real risk: follow the manual’s warnings for fuel, hot coolant, batteries, supported assemblies, and hydraulic brake work, and use a qualified technician when the job exceeds your training or equipment.