2004–2006 Kawasaki 900 STX (JT900-E1/E2/E6F) Service Manual (P/N 99924-1327-01)

• Coverage: 2004-2006 Kawasaki 900 STX base-manual content. Factory identification, specification, and wiring pages are labeled JT900-E1; some model/year applications require a separate blue-title supplement, which is not included.
• Covers major engine repair work: top-end disassembly and reassembly, compression testing, cylinder/piston/ring inspection, complete engine removal and installation, magneto flywheel and stator service, crankcase splitting, and crankshaft/connecting-rod checks.
• Details carburetor/fuel-pump removal and overhaul, carburetor synchronization and high-altitude adjustment, throttle/choke/oil-pump/Smart Steering cable setup, reed-valve inspection, and oil-pump bleeding and performance testing.
• Takes drive-shaft holder and jet-pump work through removal, bearing and seal replacement, disassembly, reassembly, runout and impeller-clearance inspection, plus steering, reverse-bucket, shift-cable, and steering-nozzle service.
• Provides ignition fault isolation, charging and starter tests, sensor and multifunction-meter checks, and Smart Steering sensor/actuator diagnosis using the JT900-E1 Wiring Diagram, Kawasaki Smart Steering System Circuit, and dedicated flowcharts.
• A 244-page PDF organized into 16 chapters, with periodic maintenance, cooling and bilge flushing, storage preparation and return-to-service procedures, symptom troubleshooting, cable/wire/hose routing, exploded assembly views, torque and locking-agent tables, wear limits, clearances, and electrical test data.

Written primarily for trained mechanics in a properly equipped shop, this manual also supports owners who already understand basic mechanics, proper tool use, and workshop procedures for basic maintenance and selected repair work. Owners without that background are directed to qualified mechanics.

Engine Repair and Fuel-System Service

The JT900-E1 specification pages identify an 891 mL, water-cooled, crankcase-reed three-cylinder two-stroke with triple Keihin CDCV carburetors, digital DC-CDI, oil injection, and direct drive. Top-end repair data covers cylinder-head warp, cylinder wear, piston diameter, piston-to-cylinder clearance, ring-groove condition, and ring end gap. Bottom-end sections add coupling-damper inspection, flywheel and stator removal, crankcase assembly, connecting-rod clearances, main-bearing wear, and crankshaft runout. Together, these sections support measured inspection during a rebuild rather than only routine tune-up work.

Carburetor and fuel-pump procedures include disassembly, cleaning, vacuum-piston and diaphragm checks, float-arm adjustment, synchronization, and high-altitude setup. Separate sections handle the intake manifold, reed valves, flame arrester, fuel tank and tap, oil tank and filter, expansion chamber, exhaust manifold, and water-box muffler.

Jet Pump, Drive, Steering, and Hull

Drive-shaft holder service specifies bearing and grease-seal arrangement, coupling alignment, and runout checks. Jet-pump coverage includes bracket sealing, pump-shaft and pump-cap bearing service, grease-seal installation, impeller removal and installation, and pump-case/impeller wear inspection. Steering content addresses the cable, handlebar and steering shaft, reverse bucket, shift cable, and shift-lever shaft. The hull chapter supplies removal and installation coverage for the hatch cover, mirrors, stabilizers, storage case, crossmember, bumpers, trim seals, and other rubber parts, along with a hull-replacement sequence.

Electrical Diagnosis, Diagrams, and Tools

Electrical repair coverage runs from battery charging and starter-motor overhaul to charging-coil, regulator/rectifier, ignition-coil, CDI igniter, sensor, switch, fuse, and multifunction-meter tests. The Smart Steering section covers steering-position sensor and magnet service, sensor-clearance inspection, input/output voltage checks, system testing, and actuator removal, installation, and inspection.

Reference material includes the Fuel System Diagram, JT900-E1 Wiring Diagram, Kawasaki Smart Steering System Circuit, Flow Chart of Kawasaki Smart Steering System, Ignition System Troubleshooting chart, and illustrated Cable, Wire and Hose Routing views. Named service tools include Piston Pin Puller Assembly 57001-910, Flywheel Puller Assembly 57001-1405, Impeller Holder 57001-1393, Impeller Wrench 57001-1228, Hand Tester 57001-1394, and Needle Adapter Set 57001-1457.

Repair Cautions

The manual flags two specific repair traps: excessive force during impeller grease-seal installation can damage the seal, while disconnecting the CDI igniter with the ignition on or removing battery leads while the engine is running can damage the igniter. Fuel-system work, high-voltage ignition tests, rotating-component checks, and engine-running procedures require the stated fire-prevention, electrical, and cooling-water precautions.