2001–2006 Yamaha YZ250LC, YZ250N1, and YZ250(N) Service Manual (P/N 5MW-28199-30)

This package contains the year-specific Yamaha Owner’s Service Manuals for 2001 through 2006 YZ250 models, rather than one 5MW manual stretched across six model years. That distinction matters when matching regional model codes, carburetor and electrical data, cable routing, specifications, and repair procedures to the bike on the stand.

• Year-specific coverage: 5MW, 5NX, 5UP, 5XF, and 1P8 model-code families for the USA, Canada, Europe, Australia, New Zealand, and South Africa.
• Major engine repair work: carburetor and reed valve, top end, clutch and primary drive, YPVS governor, water pump, CDI magneto, crankcase/crankshaft, and transmission/shift mechanisms.
• Chassis and diagnosis: wheels, hydraulic disc brakes and bleeding, front fork, steering, swingarm, rear shock, wiring, ignition, solenoid-valve, and TPS testing.
• Nine PDF files / 3,874 pages: six English/French/German/Italian annual manuals, a separate 270-page U.S. 2005 YZ250T1 manual, and 2003/2005 exploded-view parts catalogues.

Year-by-Year Model and Publication Coverage

The annual editions run from July 2000 through May 2005. The separate U.S. 2005 manual is P/N LIT-11626-18-34 / 1P8-28199-10. Identification pages locate the steering-head VIN or frame serial number, the engine serial number, and the model label beneath the seat. Regional tables also distinguish model-dependent dimensions, compression and combustion-chamber configurations, carburetor data, and electrical equipment such as the neutral-switch circuit omitted from the U.S. and Canadian versions.

Workshop Procedures and Diagnostic Depth

The engine chapters cover carburetor removal and internal inspection, reed-valve checks, top-end disassembly and measurement, piston service, clutch and primary-drive repair, kickstarter and shift-shaft work, YPVS governor service, water-pump repair, flywheel/CDI magneto removal, complete engine removal, crankcase separation, crankshaft service, and transmission/shift-cam/shift-fork disassembly and reassembly.

Chassis sections address wheel bearings and spokes, drive-chain alignment, front and rear brake master cylinders and calipers, brake-system bleeding, front-fork disassembly and seal/oil service, steering-head work, swingarm and linkage bearings, and rear-shock removal, spring, bearing, inspection, adjustment, and installation.

Factory inspection charts make the electrical section useful for fault isolation. The no-spark chart works through the spark-gap test, connections, engine-stop switch, ignition-coil windings, plug cap, CDI magneto pickup/source coils, regional neutral switch, and CDI unit. Separate charts cover solenoid-valve operation and coil testing, plus TPS resistance, variable output, replacement, adjustment, and input-voltage checks.

Track-side tuning is covered in similar depth. The manual explains how temperature, humidity, and altitude affect mixture; maps the pilot circuit, needle, throttle valve, power jet, and main jet against throttle opening; and supplies symptom-based carburetor-setting tables. Chassis tuning covers final-drive ratio and sprocket selection, tire-pressure adjustment, front-fork oil/spring/damping setup, rear-spring preload, and compression/rebound adjustment.

Specifications, Diagrams, Parts References, and Tools

Reference data includes maintenance intervals, pre-operation checks, torque-check points, component torque tables, capacities, wear and runout limits, clearances, electrical test values, jetting data, and suspension settings. Useful visual material includes cable-routing diagrams, the electrical-components and wiring diagram, ignition/solenoid/TPS inspection charts, engine and transmission exploded assemblies, front-fork exploded views, and suspension symptom/adjustment charts.

Special-tool tables cross-reference North American YM/YU numbers with international 90890 numbers. Listed examples include the YU-1135-A / 90890-01135 crankcase separating tool, YM-1189 / 90890-01189 flywheel puller, YU-1304 / 90890-01304 piston-pin puller, YU-24460-01 / 90890-01325 radiator-cap tester, YM-91042 / 90890-04086 clutch holding tool, and YM-34487 / 90890-06754 ignition checker.

The 2003 parts catalogue covers U.S. model code 5UP1, production code 010, from VIN JYACG13C63A000034 onward. The 2005 catalogue covers YZ250T1 model code 1P81. Their exploded views support parts identification across the engine, transmission, frame, suspension, wheels, brakes, controls, and electrical equipment. Parts catalogues for the other model years are not included. The 2005 catalogue references a separate Assembly Manual, LIT-11666-18-33, which is also outside this set.

Several cautions address expensive repair mistakes. Yamaha specifies a case splitter and warns against forcing the crankcase halves or striking gasket mating surfaces, which can damage the sealing faces. The crankshaft and piston pin use dedicated puller/installer tools rather than a hammer, protecting bearings, alignment, and piston components. Fork-seal work requires care not to scratch the inner tube, where damage can ruin a new seal and cause leakage.

The nitrogen-filled rear-shock cylinder and reservoir are an important scope limit. The manual covers removal, spring and bearing work, inspection, adjustment, and installation, but not internal disassembly of the pressurized body. Brake, ignition, crankcase, and suspension repair should follow the correct year/model section and Yamaha safety notes before the machine returns to closed-course competition use.