1994–1996 Yamaha YZ125G1, YZ125LC, YZ125(G) Owner's Service Manual (P/N LIT-11626-09-56)

This Yamaha Owner's Service Manual covers the 1994–1996 YZ125 series, including the YZ125LC, YZ125G1, and YZ125(G) market versions for Europe, the United States, Canada, Australia, New Zealand, and South Africa. Publication P/N LIT-11626-09-56, first edition July 1994, combines operating guidance with maintenance, tuning, and engine and chassis repair procedures.

• Engine repair: Cylinder-head, cylinder, and piston inspection; power-valve and YPVS governor service; crankcase separation; and crankshaft removal and installation.

• Clutch and transmission: Clutch assembly, primary drive and driven gear inspection, kick-start mechanism service, and shift-cam and shift-fork removal and reassembly.

• Fuel and cooling: Mikuni TMX36SS carburetor disassembly, reed-valve inspection, radiator and cap pressure tests, and water-pump impeller and oil-seal service.

• Brakes and running gear: Front and rear caliper and master-cylinder repair, brake bleeding, wheel-bearing replacement, swingarm linkage service, and steering-head adjustment.

• Suspension and race preparation: Telescopic fork overhaul, rear shock spring replacement, damping and preload adjustment, regular inspections, break-in procedures, and suspension-setting charts.

• Ignition diagnosis: Wiring diagram, component locations, regional troubleshooting charts, CDI magneto and ignition-coil tests, and ignition-timing inspection and adjustment.

The repair sections suit experienced mechanics with precision measuring equipment and the specified service tools; the operating and routine-maintenance sections also address owners preparing their machines for racing.

Engine, YPVS, and Transmission Repair

Chapters cover disassembly, inspection, and reassembly of the 4PE-series engine. The piston-to-cylinder matching chart pairs cylinder identification letters with piston color marks, helping select the correct replacement piston before assembly. Power-valve inspection covers carbon removal, wear checks, and movement checks.

Exploded assembly views, sectional sketches, and removal tables accompany clutch, crankshaft, and transmission work. The text explains shift-fork positioning and shift-cam segment alignment, with wear limits for the related parts. Crankcase service identifies the separating tool YU-01135 / 90890-01135 and its associated service procedures.

Mikuni Carburetor Tuning and Cooling-System Service

Carburetor settings: Separate baseline tables distinguish European carburetor identification mark 4PE10 from 4PE00 for the other listed markets. Throttle-opening diagrams and symptom-based setting charts connect jet and needle selection with engine response, weather, and track conditions. The tuning section also distinguishes the grooved pilot jet from the earlier design to prevent incorrect parts selection.

Water-pump repair: The impeller-shaft and seal procedures identify the seal lip and retaining spring as vulnerable during shaft installation. Radiator inspection and cooling-system pressure tests complement the pump work. Hot coolant can cause scalding; follow the manual's cooling-system precautions.

Forks, Rear Suspension, and Brake Assemblies

Fork overhaul extends to the damper rod, base valve, bushings, and oil seals, with oil-level measurement and reassembly checks. Yamaha recommends dealer maintenance for the front fork. A specific assembly caution explains how a falling damper-rod assembly can damage the valve inside the inner tube.

Rear suspension coverage includes link-type Monocross linkage inspection, shock removal, spring replacement, and preload and damping adjustment. The manual warns against disassembling the nitrogen-charged shock cylinder or reservoir; these instructions do not provide an internal shock rebuild.

Brake sections include piston and seal inspection, master-cylinder cup orientation, and hydraulic-system bleeding. Steering-bearing checks, cable routing diagrams, torque-check point charts, and component-specific fastener tables support chassis service. Suspension tuning adds spring-selection charts and fork load-versus-stroke graphs.

CDI Ignition Fault Finding

Separate ignition inspection charts cover U.S./Canadian machines and the other markets. Lead-color references, connector views, and pickup- and source-coil tests help isolate a no-spark fault before CDI-unit replacement. The electrical section also documents the engine-stop switch, ignition coil, spark testing, and dial-gauge timing checks.

Examples of Inspection Limits and Ignition Timing

These are a few of the inspection and adjustment figures included in the manual. Cylinder-head inspection specifies a warpage limit of 0.03 mm, while the reed-valve check lists a bending limit of 0.2 mm.

The ignition-timing check uses a piston position of 1.02 mm (0.040 in) before top dead center, measured with a dial gauge.

Printable PDF, Navigation, and Diagram Detail

Text access and wiring labels: PDF text search and embedded bookmarks are not available. The printed contents and section numbers provide navigation references. Small wire-color and connector labels in the wiring diagram are readable when enlarged.

One printable English PDF contains 270 pages: 235 technical pages, 15 publication and introductory pages including the index and contents, seven chapter dividers, and 13 memo pages. All are included in the total.