2007 Yamaha YZ250W Owner's Service Manual (P/N 1P8-28199-32)

Yamaha's Owner's Service Manual for the 2007 YZ250W covers the liquid-cooled two-stroke competition model and its international variants: YZ250W1 (USA/CDN), YZ250 (Europe/ZA), and YZ250W (Australia/New Zealand).

Supplied as a 270-page PDF in English, with owner information, maintenance, repair procedures, and tuning guidance across seven chapters in one file.

• Engine and transmission: Cylinder-head and piston inspection, crankcase separation, crankshaft installation, clutch repair, and inspection of the shift cam and shift forks.

• Fuel system: PWK38S Keihin carburetor disassembly, float-height inspection, reed-valve service, and main, pilot, and power-jet tuning.

• Cooling system: Radiator removal, cooling-system pressure testing, radiator-cap inspection, and water-pump impeller, shaft, bearing, and seal replacement.

• Brakes and steering: Caliper and master-cylinder repair, hydraulic brake bleeding, steering-head bearing service, and wheel and brake-disc inspection.

• Suspension: Telescopic front-fork oil-seal replacement, damper-assembly service, Monocross linkage inspection, and rear-shock spring and bearing replacement.

• Electrical diagnosis: CDI magneto and ignition troubleshooting, solenoid-valve testing, and throttle position sensor (TPS) inspection, replacement, and adjustment.

• Service references: Component-specific torque tables, fluid capacities, wear limits, electrical test specifications, maintenance interval charts, and exploded assembly views.

Owners are guided through basic maintenance, while internal repair procedures suit experienced mechanics with specialist tools; Yamaha recommends dealer servicing for the front fork.

Engine Repair and Transmission

The engine section details inspection limits and assembly procedures for the cylinder head, clutch, crankcase, and YPVS governor. The Combination of Piston and Cylinder charts identify matching size groups, helping with piston selection before replacement parts are ordered.

Crankshaft removal and installation include the specified tools, including crankcase separator YU-1135-A / 90890-01135. Transmission assembly drawings identify shift-fork positions and gear placement, followed by checks of shifting and transmission operation.

The power-valve instructions warn that handling the push-rod fastening without the specified set pin can damage YPVS components.

PWK38S Carburetor and Regional Tuning

Factory data distinguishes model codes 1P89 (USA/CDN), 1P8A (Europe), and 1P8C (Australia/New Zealand/ZA). Carburetor identification marks, jetting, needle-clip positions, and pilot-air-screw reference settings vary by region.

Combustion-chamber specifications distinguish 21.0 cm³ USA/CDN cylinder heads from 21.5 cm³ versions for Europe, Australia, New Zealand, and South Africa.

The Examples of Carburetor Setting Depending on Symptom charts relate poor acceleration, unstable running, and other symptoms to the relevant fuel circuits. Separate tables account for atmospheric and track conditions, and list optional jets and needles by part number.

The main nozzle is press-fitted and is not replaceable; the tuning section explains jet-needle selection for this carburetor. Routine service also covers air-filter care, transmission-oil changes, and regional silencer-fiber replacement procedures.

Front Fork, Monocross Suspension, and Brakes

Front-fork repair extends to base-valve inspection, damper bleeding, and inner- and outer-tube checks. The specified fork seal driver is YM-A0948 / 90890-01502.

The fork instructions identify a specific assembly risk: dropping the damper assembly into the inner tube can damage the internal valve.

Suspension Setting tables address symptoms such as bottoming, poor initial movement, and unstable handling. Spring-selection information distinguishes titanium and steel rear-shock springs and their identification marks.

Rear-shock coverage includes removal, spring replacement, mounting bearings, and external adjustments. The nitrogen-charged cylinder and reservoir are excluded from disassembly; Yamaha expressly warns against opening them.

Brake sections include piston-seal and master-cylinder-cup inspection, assembly orientation, bleeding, and leak checks. Follow the manual's brake and suspension safety precautions and checks before riding.

CDI, Solenoid Valve, and TPS Troubleshooting

The Wiring Diagram provides the electrical schematic and connector layouts; the Cable Routing Diagram shows harness placement. The neutral-switch circuit is identified for models outside the USA and Canada.

The Ignition System troubleshooting flowchart distinguishes spark-plug-cap, ignition-coil, pickup-coil, and source-coil tests. Separate procedures cover ignition-timing checks, solenoid operation and resistance, and TPS input/output voltage measurements and adjustment.

PDF Search, Navigation, and Diagram Detail

The manual text is searchable, but the cover and some labels embedded in illustrations are not. Embedded bookmarks provide section navigation, although the top-level Electrical and Tuning entries lead to the contents page; small wiring labels are best read enlarged. The total includes one cover page, 11 introductory, index, and contents pages, and two memo pages.