1973–1975 Yamaha TX500, TX500A Service Manual (P/N LIT 11613-71-01)

• 1973 TX500 / 1974 TX500A coverage in a 186-page PDF, Yamaha publication LIT 11613-71-01. July 1973 first edition; May 1974 revision; June 1975 third printing.
• Engine removal and cylinder-head repair for the DOHC eight-valve parallel twin, including cam-chain cutting/riveting, cam timing, and omni-phase balancer weight indexing and chain-tension adjustment.
• Drivetrain procedures cover crankcase separation, transmission gear and shift-fork inspection, clutch assembly, and the kick-start mechanism.
• Twin Keihin CV32 carburetor service includes float-level adjustment, vacuum-gauge synchronization, and factory tuning notes for altitude changes and midrange surging.
• Chassis coverage extends to front-fork and swing-arm service, front hydraulic disc-brake overhaul and bleeding, and rear drum-brake inspection.
• Electrical testing addresses the brushless AC generator, starter motor, breaker-point ignition timing, and IC voltage regulator, supported by schematics and fault-finding charts.

DOHC Valvetrain and Wet Sump Lubrication

The top-end sections cover camshaft journal inspection, rocker-arm shafts, valve-guide replacement, seat reconditioning, and piston-and-cylinder measurement. The Valve Timing diagram supports the explanation of DOHC valvetrain geometry. Yamaha warns that camshaft removal in the wrong timing position can let valve-spring force turn the shafts, damaging the camshafts, caps, and retaining studs.

The wet sump lubrication system uses separate feed and scavenging trochoidal pumps. The Oil Delivery Schematic follows their connections to the filter, crankshaft, and camshafts; the service sections address strainers, the oil release valve, and the shared pump/tachometer drive.

The Route of Power Flow from the Starter Motor illustration explains the one-way roller-lock starter clutch. Clutch assembly coverage addresses steel-plate indexing, friction-plate wear, plate warpage, and spring inspection.

Crankshaft Bearings, Specifications, and Tools

When rebuilding the bottom end, the crankshaft assembly instructions guide you through selecting the correct bearing inserts based on specific housing and shaft diameter codes. Plastigage checks support clearance inspection, but the insert-selection section also refers to the separate TX750 Service Manual, which is not included.

Fastener torque tables cover M8, M10, and M12 hardware alongside component-specific tightening data. The specifications also include piston-to-bore clearances, valve settings, wear limits, fluid capacities, and electrical test values. Special-tool references identify the cam-chain cutting/riveting tool 90890-01112 and clutch holding tool 90890-01069.

Serial-Specific Parts and Service Bulletins

The appendix distinguishes factory changes that affect repair planning and parts selection. Service News 320 documents special initial valve setup for TX500 engines 007287–008776, associated with the transition to pressed-in valve seats.

Bulletin M4-019 identifies revised second- and fifth-gear components from TX500A E/N 100198. Retrofitting the revised design requires the matched four-gear set, not individual substitutions.

Service News 382 separates early left-hand-thread rear-hub retainers from the later right-hand-thread assembly introduced at TX500A E/N 371-107395. These hub components are interchangeable only as a matched assembly.

Other bulletins address camshaft-case oil leaks, cylinder-head retorquing, and revised valve guides and seals. The appendix is a modification reference, not a complete parts catalog.

Chassis Inspection and Electrical Diagnosis

Rear suspension coverage includes damping checks, while wheel inspection addresses bearings, spokes, and rim runout. Brake repair cautions explain how petroleum contamination damages hydraulic seals and specify replacement of caliper bridge bolts after disassembly.

The Operation Circuit of IC Voltage Regulator diagram accompanies bench and on-bike charging-system checks. The Wiring Diagram (U.S.A.) and Cable Routing Diagrams cover electrical connections and the placement of harnesses, control cables, and brake hoses.

Symptom-based troubleshooting separates hard starting, poor idle, weak midrange or high-speed operation, overheating, and blue exhaust smoke. This page reviews the contents of the publication and does not replace the diagnostic steps and repair procedures in the manual.