1981 Yamaha XJ550 Factory Service & Repair Manual (P/N LIT-11616-02-29)

• Exact coverage and file scope: Covers the 1981 Yamaha XJ550RH, identified by starting serial 4U8-000101. The 143-page PDF contains 124 consecutive XJ550RH service pages spanning seven chapters, from Chapter 1 page 1-1 through Appendix page 7-28, plus a 19-page XJ550H reference extract covering printed pages 2-20.
• Engine repair: Details in-frame cylinder-head, cylinder, and piston work; full engine removal; crankcase separation; cylinder-head and valve service; cam-chain timing; crankshaft and bearing inspection; and clutch, oil-pump, transmission, starter-clutch, generator, and starter service.
• Carburetion and tuning: Covers valve-pad selection charts, cam-chain and ignition-timing checks, compression testing, YICS-assisted four-carburetor synchronization, Mikuni BS28 disassembly and inspection, fuel-level setting, and air-cleaner/crankcase ventilation service.
• Chassis and brakes: Includes front and rear wheel service, bearing replacement, rear drum inspection, front disc caliper and master-cylinder repair, brake bleeding, fork disassembly and seal replacement, steering-head service, swingarm bushings, rear shocks, drive chain, and sprockets.
• Electrical diagnosis: Provides circuit-level tests for electric starting, charging, TCI ignition, lighting, signals, self-canceling flashers, switches, battery, oil-level warning, and fuel sender.
• Workshop reference: Lists Yamaha special tools by P/N and supplies component-specific torque tables, fluid capacities, wear limits, clearance data, electrical test values, lubrication charts, cable-routing views, wiring schematics, and exploded parts illustrations.

The service depth and equipment requirements make this manual suited to professional technicians and experienced owners already familiar with motorcycle repair, precision measurement, carburetor synchronization, and electrical test equipment. Yamaha marks several scheduled operations for dealer or qualified-mechanic service, while the overhaul chapters assume access to the listed special tools rather than teaching basic workshop practice.

XJ550RH and XJ550H Scope

The main repair chapters apply to the XJ550RH. This portion of the scan begins at Chapter 1 rather than with an original cover or imprint page. The appended XJ550H material is not a second complete repair manual; it supplies maintenance charts, specifications, torque data, cable routing, and a wiring diagram. Those H tables are not duplicates of the RH data. They contain different primary-drive, camshaft, front-fork, tire, fuel-tank, chassis-geometry, and BS28 carburetor identification and calibration information.

Engine and Carburetor Repair Depth

The engine section distinguishes in-frame service from full removal: the cylinder head, cylinder, and pistons can be removed without taking the engine out. Overhaul coverage continues through valve-guide replacement, valve-seat cutting and lapping, valve-lifter inspection, and adjustment-pad selection. It also documents camshaft and cam-chain inspection, cylinder and piston measurement, crankshaft and bearing-clearance checks, oil-pump inspection, clutch and transmission work, starter-clutch service, crankcase assembly, and cam-timing setup.

The carburetor chapter covers the four Mikuni BS28 constant-velocity units as a bank, including vacuum-piston and diaphragm inspection, float-valve service, fuel-level adjustment, and synchronization with the YICS passage isolated. It also identifies the factory-set pilot screws and explains why routine cleaning does not require separating the carburetor bodies.

The cautions are model-specific: cam-lobe contact with the tappet adjusting tool can fracture the cylinder head, and turning a cam incorrectly during timing work can bend a valve.

Chassis, Brakes, and Electrical Diagnosis

Chassis repair extends to wheel bearings, the rear drum, the front hydraulic disc system, fork seals, steering-head bearings, swingarm bushings, shocks, chain, and sprockets. Detailed tubeless-tire and cast-aluminum-wheel servicing is expressly referred to a separate Yamaha manual. Brake and fork warnings address stable motorcycle support, disc contamination, and internal seal damage from unsuitable cleaning solvents.

Diagram coverage includes the full XJ550RH wiring diagram and separate electric-starting, charging, TCI ignition, lighting, and signal-system circuit diagrams. The electrical chapter adds component tests and fault checks for the starter and cutoff relays, A.C. generator, IC regulator/rectifier, ignition and pick-up coils, headlight relay, self-canceling turn signals, switches, warning circuits, and fuel sender.

Named tools include the tappet adjusting tool P/N 90890-01245-00, rotor puller P/N 90890-01080-00, YICS shutoff tool P/N TLM-11080-25-00, fuel-level gauge P/N 90890-01312-00, pocket tester P/N 90890-03104-00, and Electro Tester P/N 90890-03021-00.