Yamaha WR500 / WJ500 / WR650 / MJ650T Service Manual Collection, 1986–1993

The sections provide model-specific maintenance, diagnosis and repair procedures. WJ500-specific service is concentrated in the first two sections; the later material adds revised engine, carburetor and hull procedures.

Coverage limitations: Original page sequences have gaps at engine disassembly page 4-5 in the 1987–1989 section; carburetor inspection page 4-9 and WR650 disassembly page 5-9 in the 1990–1991 section; and engine/intermediate-shaft pages 5-48–5-49 in the 1993 section. The separate Water Vehicle FRP Repair Manual referenced for insert-nut repairs is not included.

PDF Bookmarks, Diagram Detail and Page Count

Search and navigation: PDF text search is not available. Embedded bookmarks cover chapters and many individual procedures, although the later manuals’ main bookmarks incorrectly return to the beginning. Small wiring labels and dense CDI test tables are readable with zooming on the checked pages.

The ZIP contains one printable, 580-page PDF. The total includes the five storage-insert pages listed above.

Engine, Fuel and Jet-Pump Service

The following highlights are selected contents, not a complete table of contents. Other topics include fuel-tank check-valve inspection and drain-plug checks.

• Engine repair: Step-by-step removal, disassembly, inspection and reassembly procedures cover reed valves, pistons, crankshafts, intermediate shafts and engine/coupling alignment.

• Fuel-system service: Diaphragm carburetor and fuel-pump repair includes needle-valve checks, float-arm inspection, mixture adjustment and model-specific fuel-hose routing diagrams.

• Jet-pump overhaul: Impeller removal, driveshaft bearings and seals, shaft inspection and shim-selection charts support pump repair and clearance adjustment.

• Electrical diagnosis: Wiring diagrams and CDI circuit documentation accompany ignition testing, starter-motor repair, starter-relay inspection and rectifier-regulator checks.

• Steering and hull work: Procedures distinguish WJ500 steering-post service from WR500/WR650 column assemblies; later sections add ride-plate adjustment, bilge-system service and deck hardware.

• Maintenance and storage: Inspection schedules, lubrication points and seasonal care cover cooling-system flushing, engine fogging, fuel treatment and battery maintenance.

Written for Yamaha dealers and their mechanics, these service procedures call for the measuring equipment and special tools identified in the manuals.

Engine Layouts and Carburetor Details

The engine chapters distinguish the 6K8-powered WR500/WJ500 from the 6M6-powered WR650/MJ650T. Cylinder and piston measurements are supported by piston-ring checks, bearing inspection, water-jacket examination and separate assembly instructions for the different engine layouts.

Fuel connections: Fuel System Diagrams and hose-routing guides distinguish ON, RES, supply and return connections. These model-specific illustrations help identify the correct connections during fuel-system repair.

Carburetor cautions explain how unsuitable solvents can damage synthetic rubber parts and how careless cleaning can damage diaphragms. The cleaning instructions differ between sections and components, so the applicable carburetor procedure matters.

Tools and assembly views: References include flywheel puller YB-6117 and, in the later tool list, WR500 gauge block YW-06367 and CDI tester YU-91022-B. Exploded views identify component relationships, lubrication points and sealing locations.

Starting, Ignition and Cooling Diagnosis

Troubleshooting charts separate an engine that will not crank from one that cranks without starting, then address weak spark, irregular running, stalling and failure to shut off. This distinction helps direct diagnosis toward the starting circuit, fuel supply, ignition or compression checks.

Component tests extend to charge and pulser coils, starter brushes and armature, and the overheat thermo switch. CDI resistance tables identify test connections and explain how tester characteristics can affect readings.

The Wiring Diagrams and CDI Circuit Diagram are supplemented by the later Cooling System Diagram and Ventilation System Diagram. These distinguish cooling-water, exhaust, bilge, fresh-air, vapor and drain-water paths. Fastener torque tables, wear limits and electrical test specifications accompany the repair material.

Hull, Steering and Seasonal Care

Hull repair coverage addresses light and deep scratches, punctures, graphic replacement and damaged insert-nut mountings. Later chapters document gunwale and mat replacement, hood hinges and latches, and deck hardware.

The WJ500 steering-post section warns that incorrect tightening can loosen the mounts and crack the post. Ride-plate stopper notes identify WR500 (MJ500T), WR500 (MJ500S) and WR-LX (MJ650T) configurations for that mounting detail; these references do not extend the general model coverage to every MJ500T or MJ500S configuration.

The storage insert covers cooling-system flushing, engine fogging, fuel treatment and battery care. Follow the manual’s precautions for gasoline vapors and rotating jet-pump parts, and consult a qualified technician if you are unsure about a complex repair.

Selected Jet-Pump and Ignition Test Values

For the early WR500/WJ500 jet pump, the specifications list 0.3 mm impeller clearance and a 0.6 mm service limit. The accompanying shim-selection chart relates measured tip clearance to changes in shim thickness.

For the same models, the CDI inspection section specifies pulser-coil resistance of 102 Ω ±10% at 20°C, measured between White/Red and Black. The test illustrations identify the corresponding connections.