Yamaha YZ125(W)/W1 (2006) Owner’s Service Manual (P/N 1C3-28199-32)

Yamaha’s Owner’s Service Manual (P/N 1C3-28199-32), first edition May 2006, covers the YZ125 for Europe and South Africa, the YZ125W for Australia and New Zealand, and the YZ125W1 for the U.S. and Canada. It combines operating instructions and routine maintenance for closed-course competition with workshop procedures and race setup data.

PDF Search, Bookmarks, and Languages

Finding procedures and wiring details — Search the manual text or use the embedded bookmarks to find service topics in each language. Chapter-level bookmarks lead to the contents pages, with individual service topics linked below them. The small connector labels and wire color codes inside the CDI schematic are readable when zoomed in and are part of the diagram image.

The download is one printable PDF with English, French, German, and Italian content. Its 576 pages include 571 pages through the end of the tuning chapter, three memo pages, and two repeated pages showing the publication imprint and cover.

YPVS, Chassis Service, and Race Setup

These selected workshop topics show the scope of the manual. Other sections cover starting and break-in, and cleaning and storage.

• Routine inspection: Maintenance intervals and pre-ride checks, with adjustment procedures for the controls and drive chain.
• Engine and transmission: Engine removal and installation, top-end and YPVS service, crankcase and crankshaft work, clutch and primary drive repair, and inspection of the transmission, kickstarter, and shift mechanisms.
• Fuel and cooling: Carburetor and reed-valve service, radiator cap and cooling-system pressure tests, and water-pump inspection.
• Brakes and chassis: Caliper and master-cylinder overhaul, brake bleeding, and service procedures for the wheels, steering head, front fork, swingarm, linkage, and rear shock spring.
• CDI ignition: A wiring diagram, a component-location drawing, and a no-spark diagnostic flowchart, with ignition timing and resistance checks.
• Race setup: Market-specific carburetor jetting, final-drive ratio selection, and front and rear suspension tuning charts organized by handling symptom.

The operating and maintenance sections are written for owners. Internal engine work and electrical diagnosis are suited to mechanics or experienced owners familiar with the specified pullers, dial gauges, and electrical testers.

Engine Inspection and Carburetor Settings

Wear checks. The engine chapter covers cylinder-head and cylinder condition, piston and ring wear, crankshaft runout and connecting-rod play, clutch plates and springs, and inspection of the shift cam, forks, bearings, and seals. The Yamaha Power Valve System (YPVS) procedures include linkage, governor, alignment, and free-movement checks.

Jetting by market. Yamaha lists different jet-needle data for U.S. and Canadian models and for the other markets. The tuning chapter relates the pilot circuit, needle, and main jet to throttle opening, weather, altitude, and track conditions so you can identify which circuit the manual addresses for a given setup problem.

Assembly References and Service Limits

Exploded views and job charts identify which parts need to come off for a given repair. Separate routing diagrams show cable and hose placement during reassembly, and the specification tables give component torque values, clearances, and wear limits.

Special tools. The regional tool list identifies the YU-1135-A / 90890-01135 crankcase separator, the YU-90050-series crankshaft installer, the YM-01500 / 90890-01500 and YM-01501 / 90890-01501 fork tools, and the YU-3112-C / 90890-03112 pocket tester. It also lists the YM-34487 dynamic spark tester and 90890-06754 ignition checker.

Repair cautions. Yamaha warns against hammering the crankshaft or striking the crankcase mating surfaces. Scratches on those surfaces can call for crankcase replacement. The fork section covers the damper assembly, base valve, slide bushings, and oil-seal protection, and Yamaha recommends dealer maintenance for the fork.

Rear-shock procedures cover removal, spring service, and adjustment. Yamaha warns against opening the high-pressure nitrogen cylinder or reservoir and assigns gas discharge for disposal to its dealers. Support the machine securely and follow the manual’s safety procedures during engine, brake, and suspension work.

Sample Fork, Cooling, and Ignition Specifications

The front-fork oil capacity table specifies 522 cm³ for Europe and 527 cm³ for the U.S., Canada, South Africa, Australia, and New Zealand. The cooling-system inspection gives a radiator cap opening pressure of 95–125 kPa.

For ignition fault isolation, Yamaha specifies 0.24–0.36 Ω at 20°C (68°F) for the ignition coil’s primary winding. The flowchart also covers the engine-stop button, plug cap, and the CDI magneto’s pickup and source coils.