1999–2006 Yamaha YZ250(S)/LC Owner's Service Manual (P/N 5XF-28199-30)

Yamaha's Owner's Service Manual for the 1999–2006 YZ250(S)/LC, publication 5XF-28199-30, includes regional specifications for 5XF1 (USA, Canada and South Africa), 5XF2 (Europe), and 5XF4 (Australia and New Zealand).

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

• Clutch and transmission: Clutch disassembly, primary-drive service, gear inspection, and assembly of the shift cam, shift forks and transmission shafts.

• Fuel and cooling: Keihin PWK38S carburetor and reed-valve service, jetting charts, radiator testing, and water-pump seal and impeller service.

• Brakes and chassis: Front and rear caliper and master-cylinder overhaul, brake-system air bleeding, wheel-bearing replacement, steering service, and swingarm linkage inspection.

• Suspension: Front-fork disassembly, seal replacement and oil-level setup; rear-shock removal, spring and bearing service, and preload and damping adjustments.

• Electrical diagnosis: Wiring and cable-routing diagrams, ignition troubleshooting, solenoid-valve tests, and throttle position sensor (TPS) inspection, replacement and adjustment.

The repair sections suit mechanics and experienced owners equipped for internal engine work, dimensional inspection, and electrical testing.

Engine Internals, YPVS and Transmission

Exploded views and job instruction charts identify each assembly's removal extent, helping you avoid dismantling parts that can remain in place. Piston/cylinder matching charts distinguish the A–D size groups, while piston-ring sectional views and inspection tables document clearances and wear limits.

The YPVS instructions flag the risk of damaging power-valve components during push-rod removal or installation without the set pin. Crankcase work identifies the separating tool as YU-1135-A for the USA and Canada, or 90890-01135 for other markets.

Maintenance interval charts organize checks around break-in and racing use, with component torque tables supporting the repair procedures.

Clutch inspection covers friction-plate thickness, plate warpage and spring length. Transmission checks address gear dogs, shift-fork grooves and shift-cam condition, with assembly diagrams showing shaft and fork placement.

Carburetor Settings and Cooling-System Tests

Carburetor setting charts distinguish European jet-needle specifications from those used in the other markets and relate throttle opening and running symptoms to the metering components. Reed-valve inspection includes bending limits and stopper-height data.

Cooling coverage combines radiator-cap and cooling-system pressure tests with water-pump disassembly and seal inspection. The pump section explains when dismantling is warranted, including abnormal changes in coolant level or milky transmission oil.

Fork Service, Rear-Shock Limits and Brakes

Front Fork Disassembly views cover the damper rod, base valve, bushings and seals. The assembly notes identify the internal-valve damage that can result if the damper rod drops into the tube. Yamaha recommends dealer maintenance for the front fork.

Rear-shock procedures cover removal, spring and mounting-bearing service, and suspension setup. Internal overhaul of the nitrogen-filled cylinder and reservoir is outside this coverage. Yamaha warns against dismantling these components; the gas-release instructions concern dealer disposal.

Swingarm service includes the relay arm, connecting rod and polylube bearings. Front and rear brake sections cover master-cylinder cup orientation, caliper piston seals, bleeding and post-assembly leak checks.

Ignition, Solenoid Valve and TPS Diagnosis

The ignition inspection chart traces a no-spark fault through connections, the stop button, spark-plug cap, ignition coil and CDI magneto before CDI-unit replacement. The wiring diagram identifies connector positions and wire colors, while cable-routing diagrams show harness and hose placement.

Separate solenoid-valve and TPS tests include component resistance checks and lead identification. TPS replacement also covers output-voltage adjustment and input-voltage inspection.

A Preview of Cylinder-Head and Piston Specifications

These examples are a small selection of the manual's engine inspection and assembly data.

Combustion chamber capacity is 21.0 cm³ for USA, Canada, South Africa, Australia and New Zealand models, and 21.5 cm³ for Europe.

Standard piston clearance is 0.045–0.050 mm, with a 0.1 mm service limit. The cylinder-head nut specification is 25 Nm (18 ft-lb); the assembly section specifies staged tightening in a crisscross pattern.

Searchable PDF, Navigation and Included Pages

Text search and diagram detail: The PDF contains searchable text. Bookmarks open the cover and contents pages, with linked contents entries for the service sections. Small wire-color and connector labels are best read with magnification.

The download is one printable, 585-page PDF in English, French, German and Italian. The total includes two cover pages and four memo pages, leaving 579 pages of introductory material, contents and technical information.