1978 Yamaha SR500(E) Service Manual Supplement (P/N 1N5-28197-80)

This March 1978 first-edition Yamaha SR500(E) service manual covers the SR500E (2J2) and SR500 (2J4) versions of the air-cooled 499cc single. It supplements the XT500(C) service manual, P/N 1N5-28197-80. That base manual is required for complete service procedures and is not included in this PDF.

Navigation and diagram detail: Text search is unavailable. Embedded bookmarks use image filenames. Small wiring labels require zooming, and some switch detail is cropped from the left edge of one wiring sheet. Printed page 103 is missing; pages 28 and 29 appear in reverse order.

• Engine repair: Engine removal details, cylinder-head and clutch disassembly, primary drive gear removal, valve seat work, and cam chain tensioner adjustment.

• Carburetor service: Mikuni VM34SS disassembly, inspection and reassembly, float-level adjustment, accelerator pump service, and coasting enricher checks.

• Brake repair: Front and rear caliper and master cylinder service, pad replacement, disc inspection, hydraulic bleeding, and rear drum-brake adjustment.

• Chassis service: Cast-wheel inspection, drive chain adjustment, front fork oil changes, and steering-head installation data.

• Electrical diagnosis: C.D.I. ignition troubleshooting, pulser and charging coil tests, A.C. magneto checks, regulator and rectifier testing, and lighting-system fault tracing.

• Service references: Maintenance and lubrication charts, component torque tables, fluid capacities, wear limits, electrical test specifications, wiring diagrams, and cable routing.

Yamaha wrote this manual for authorized dealers and their qualified mechanics, with basic mechanical knowledge assumed.

Engine, Clutch and Lubrication

The inspection sections cover valve and rocker arm clearances, valve springs and guides, piston measurement, and the trochoidal oil pump's feed and scavenger rotors. Valve seat repair addresses contact width and position.

Clutch pushrod checks and kick starter alignment notes accompany the wet-clutch, crankshaft, and five-speed transmission reference data. Flywheel removal references the factory puller listed as 90890-01189.

Mikuni VM34SS Carburetor

Section views explain how the accelerator pump, pump safety valve, and coasting enricher operate. The service text covers diaphragm inspection, the tilt-type jet needle, and full-throttle adjustment.

The coasting enricher and pump safety valve covers look alike. Assembly illustrations distinguish their positions, while the float-level instructions explain the relationship between the float and the spring-loaded inlet needle.

Brakes, Forks and Market Variants

The specification tables distinguish European versions with spoked wheels and a rear drum brake from the cast-wheel, rear-disc configuration listed for other areas. Steering head bearing specifications and brake inspection limits accompany the chassis service material.

The brake section warns that cleaning solvents can swell and distort the internal seals. Before road testing, verify the front forks and disc brake assemblies against the factory inspection criteria.

Ignition, Charging and Flasher Diagnosis

The no-spark/weak-spark and poor-pickup troubleshooting charts work with pulser and charging coil test data to help isolate coil or wiring faults before replacing the C.D.I. unit.

Testing covers the I.C. voltage regulator and silicon rectifier, with stator coil resistance and magneto output data. The tool list specifies Pocket Tester 90890-03104. Yamaha also warns that a high-voltage insulation tester can damage the regulator.

Self-canceling flasher diagnosis covers the speedometer sensor and handlebar switch reset circuit; this section excludes the German-market configuration. Its circuit diagram supports the component checks.

Regional wiring diagrams distinguish continental-European, England/Belgium/France, and other-area configurations. Wire and pipe routing drawings and external views provide additional reference for component placement.

PDF Contents and Languages

Service text appears in English, French, and German; the supplied specification tables are in English. This is one printable 122-page PDF, including 111 service/reference pages, eight cable-routing, wiring-diagram and legend pages, one cover, and two foreword/notice pages.