2012 Yamaha YZ250F(B) Owner's Service Manual (P/N 17D-28199-32-E0)

The 2012 Yamaha YZ250F(B) Owner's Service Manual, document 17D-28199-32-E0, covers YZ250FB and YZ250F market versions for the USA, Canada, Europe, Australia, New Zealand, and South Africa. It combines operating guidance with maintenance, repair, and tuning information for closed-course competition use.

Text search and diagram detail: Service text is searchable, with bookmarks for chapters and individual service sections. The opening reading notice and some illustrated labels are not text-searchable. Small wiring and connector labels are clearly readable when enlarged.

• Engine repair: Engine removal, cylinder-head and crankshaft service, camshaft installation, valve-clearance adjustment, and piston inspection for the liquid-cooled DOHC engine.

• Transmission and clutch: Teardown and assembly of the constant-mesh five-speed transmission and wet multiple-disc clutch, plus shift-cam and shift-fork inspection.

• Carburetor and tuning: FCR-MX39 disassembly, float-height checks, accelerator-pump timing adjustment, and symptom-based jetting guidance.

• Cooling and lubrication: Radiator-cap and cooling-system pressure tests, water-pump service, oil-filter replacement, and oil-pump inspection.

• Chassis and brakes: Telescopic front-fork rebuilding, link-type Monocross suspension service, steering-head maintenance, brake-caliper and master-cylinder repair, and hydraulic bleeding.

• Electrical diagnosis: Wiring diagrams, CDI magneto and ignition-coil tests, ignition timing checks, and throttle position sensor inspection, replacement, and adjustment.

Owner operating guidance is included; valve adjustment and the engine, chassis, and electrical repair sections assume existing Yamaha servicing knowledge and practical skills.

Engine and Drivetrain Repair

The engine chapters cover cylinder-head, camshaft, piston, and crankshaft teardown and reassembly, with separate procedures for the balancer and kick shaft. Intake and exhaust pad-selection tables support valve-clearance adjustment, alongside timing-chain and decompression-system inspections.

Uneven camshaft-cap tightening can damage the cylinder head, caps, and camshafts; the camshaft section details the required tightening sequence.

Transmission coverage includes gear dogs, shift-fork grooves, bearings, and post-assembly shift checks. Clutch inspection covers friction-plate wear, plate warpage, spring condition, and the release mechanism.

FCR-MX39 Carburetor and Competition Tuning

Regional carburetor tables distinguish the NFPR jet needle for USA/Canada from the NFPQ needle used in the other covered markets. These distinctions help establish the correct factory baseline before selecting tuning parts.

The tuning chapter relates throttle opening and running symptoms to main-jet, pilot-jet, needle, and leak-jet settings. Routine maintenance includes race-based inspection intervals and air-filter care; exhaust service distinguishes the silencer-fiber replacement procedures for USA/Canada and other markets.

Cooling and Dry-Sump Lubrication

Cooling-system documentation covers leak testing and radiator inspection, plus water-pump impeller, shaft, bearing, and seal service. Lubrication diagrams trace the oil circuit through the filter, pump, crankshaft, camshafts, and separate oil tank.

Brakes, Steering, and Suspension

Wheel-bearing replacement, swingarm and linkage-bearing service, and front/rear brake exploded views supplement the removal and assembly procedures. Suspension setting charts relate handling symptoms to spring selection and damping adjustments.

Fork assembly notes explain how dropping the damper assembly into the inner tube can damage its internal valve.

Rear shock coverage includes removal, inspection, spring and mounting-bearing replacement, and external adjustment. Yamaha expressly prohibits disassembly of the nitrogen-filled cylinder or reservoir.

Standard rear sprockets differ by market: 50T for USA/Canada and 51T for the other covered versions.

CDI and Throttle Position Sensor Diagnosis

The ignition inspection chart follows a no-spark complaint through wiring, engine-stop switch, ignition coil, magneto, and neutral-switch checks before CDI-unit replacement is considered. That sequence helps isolate the fault before a CDI unit is replaced.

TPS charts cover resistance and input/output-voltage testing. Cable-routing diagrams and connector views identify lead colors and connections.

Torque Tables, Wear Limits, and Special Tools

Component-specific tables cover cylinder-head fasteners, the primary drive gear, oil and coolant capacities, valve and piston clearances, wear limits, and electrical test values. Exploded diagrams are paired with job instruction charts.

The special-tool list gives regional equivalents, including crankcase separator YU-1135-A / 90890-01135 and flywheel puller YM-1189 / 90890-01189.

Follow the manual's torque specifications and safety instructions for all engine, brake, and suspension work.

English PDF and Included Pages

One printable English PDF contains 193 pages total: 186 chapter pages plus seven front-matter pages comprising the cover, reading notice, foreword, two guide pages, and two contents pages. Those seven introductory pages are already included in the total.