Yamaha YZ250(P)/LC 2002 Owner's Service Manual (P/N 5NX-28199-30)

Yamaha YZ250(P)/LC Owner's Service Manual, P/N 5NX-28199-30, 1st Edition, June 2001. Covers the 2002 YZ250P1 (USA), YZ250LC (Europe), and YZ250(P) (Canada, Australia, New Zealand, and South Africa), with market-specific model codes 5NX1, 5NX2, and 5NX4.

PDF Search, Contents Links, and Languages

Search and diagram detail: Service text is searchable. Embedded bookmarks point to the cover and language-specific contents pages rather than directly to the service chapters. Small wiring color codes and connector labels are clear when enlarged.

The ZIP download contains one printable 584-page PDF with English, French, German, and Italian text. The total includes the original front and back covers, 24 pages of introductory material and indexes, two memo pages, and one blank page.

Engine Overhaul, Chassis Service, and Race Setup

The following highlights are a selection of the manual's contents. Additional topics include silencer packing replacement and cleaning and storage procedures.

• Engine repair: Engine removal and installation, crankcase separation, crankshaft and bearing service, transmission and shift-fork work, clutch and primary-drive inspection, kick/shift mechanisms, CDI magneto removal, and water-pump repair.

• Top-end and fuel-system work: Cylinder-head, cylinder, piston, ring, and YPVS power-valve service; Keihin PWK38S carburetor and reed-valve removal, disassembly, inspection, and assembly; TPS replacement and adjustment.

• Chassis and brake repair: Wheel and bearing work, brake-disc inspection, master-cylinder and caliper teardown, seal replacement, hose installation, fluid filling, and bleeding. Front-fork disassembly, steering-head bearings, swingarm/linkage service, and rear-shock removal and setup are included.

• Electrical diagnosis: CDI/TPS/solenoid wiring diagram, ignition fault-isolation chart, connector checks, spark-gap testing, ignition-coil and CDI-magneto tests, solenoid-valve checks, and TPS input/output-voltage diagnosis.

• Race maintenance and setup: Competition service schedule and pre-operation checklist, regional carburetor jetting, atmospheric and symptom charts, spark-plug heat-range selection, sprocket combinations, tire setup, and front/rear suspension tuning.

• Illustrated factory reference: Exploded removal views, ordered job charts, and follow-on inspection notes, supported by component torque data, fluid capacities, wear limits, and electrical test specifications.

Built for a closed-course competition motorcycle, this mechanic-oriented repair reference is best suited to race mechanics and experienced owners comfortable using pullers, a dial indicator, electrical test equipment, and suspension service tools.

Market-Specific Baselines

European carburetor calibration and jet-needle choices are separated from the USA/Canada/South Africa/Australia/New Zealand settings. Final-drive and chassis baselines group Europe with Canada.

Rear-spring specifications and selected fork-assembly notes are called out specifically for Europe. These distinctions matter when selecting setup parts or returning a modified bike to its factory baseline.

Top-End Inspection and Assembly Detail

The top-end chapter includes A–D cylinder/piston grade matching, clearance and wear inspection, carbon removal, and YPVS linkage alignment. Step-by-step procedures combine exploded views with job charts and assembly notes.

The manual warns against scraping the aluminum power-valve bore with a sharp tool and against hammering the crankshaft into the cases; these mistakes can damage precision surfaces, the crankshaft, or its bearings. It also specifies single-use piston-pin clips and illustrates the clip-gap position to avoid during piston assembly.

Carburetor Service and Electrical Fault Tracing

Carburetor coverage preserves the individually set pilot-air-screw reference and includes TPS replacement and recalibration rather than stopping at jet identification. The tuning section distinguishes regional needle configurations and relates mixture settings to throttle opening, atmospheric conditions, and running symptoms.

The ignition inspection chart supports tracing a no-spark fault through connections, the engine-stop button, ignition coil, and CDI magneto before CDI-unit replacement. Separate solenoid and TPS inspection sequences provide component tests and connection diagrams.

Special Tools and Workshop Illustrations

The special-tool list gives U.S./Canada numbers and 90890-series equivalents. Examples include crankcase splitter YU-1135-A/90890-01135, flywheel puller YM-1189/90890-01189, YU-90050/YM-1277 crankshaft installer components, fork-seal driver YM-01442/90890-01442, and Yamaha pocket tester YU-3112-C/90890-03112.

Representative illustrations cover the piston and power valve, transmission/shift mechanism, brake hydraulics, front fork, and swingarm linkage. Cable and hose routing layouts, piston-to-cylinder matching charts, and suspension symptom tables provide further assembly and setup references. Torque callouts accompany the assemblies, backed by general fastener and maintenance-specification tables.

Suspension Coverage and Competition Limits

The electrical section covers the race bike's CDI ignition, engine-stop button, solenoid valve, and TPS; it is not a street-equipment wiring manual.

Full front-fork disassembly is illustrated, although Yamaha recommends dealer maintenance because the internals are contamination-sensitive. The rear-shock chapter covers removal, spring and bearing work, inspection, adjustment, and installation, but not internal cylinder or reservoir teardown.

Secure the motorcycle on a suitable stand for engine, wheel, brake, or suspension work, and release fork-chamber air before the caps are removed. The rear shock contains high-pressure nitrogen; Yamaha prohibits opening its cylinder or reservoir and reserves gas-release disposal procedures for dealers.

Examples of Piston and Ring Inspection Limits

Piston-to-cylinder clearance is listed at 0.045–0.050 mm, with a 0.1 mm service limit. Installed piston-ring end gap is 0.40–0.55 mm, with a 0.95 mm limit.