Yamaha YZ250(P)/LC, YZ250, YZ250P1 & YZ250LC 2001–2002 OEM Service Manual (P/N 5NX-28199-30)

• Covers 2001–2002 Yamaha YZ250(P), YZ250P1, and YZ250LC motocross models, including liquid-cooled and regional variants
• Official Yamaha publication (P/N 5NX-28199-30, first edition June 2001) packing 584 pages of factory reference data
• Provides immediate access to 17 maintenance sections and 4 precise torque-check charts
• Delivers essential troubleshooting, diagnostic, and repair procedures in a convenient PDF format
• Details the CDI magneto, water pump, shift cam, front fork, rear shock absorber, and TPS

Manual Content and Structure

Getting the right specs fast is crucial when you have a torn-down YZ250 taking up bench space. Having the precise factory tolerances on hand streamlines your workflow and ensures reliable repairs. This service manual delivers the exact factory-recommended inspection protocols and wear limits used by Yamaha technicians. It breaks down the 5NX-series build across seven distinct chapters. You get comprehensive data on engine disassembly, top-end inspections, transmission overhauls, and the precise tuning of the YPVS governor system. Chassis service is covered in equal depth, mapping out everything from steering and suspension valving to complete electrical system routing. Navigating the mechanical and electrical layout is simplified through comprehensive wiring diagrams, detailed cable routing diagrams, exploded diagrams, internal sectional views, sequential job instruction charts, and tuning charts. To help you avoid expensive dealership labor costs, this guide includes step-by-step instructions for splitting the crankcases, completely rebuilding the telescopic front forks, and calibrating the throttle position sensor. To keep your workspace safe, always verify the bike is securely lifted on a stand and the cooling system is fully depressurized before digging into the engine cases.

Specification Highlights

Precision matters on high-revving competition two-strokes. This guide lists the exact torque settings for critical, high-stress assemblies like the primary drive gear, cylinder head studs, and steering ring nut. You will find all essential fluid parameters, including the 1.20 L coolant capacity and specific transmission oil requirements. Need quick carburetor data? The manual specs a #178 main jet for the PWK38S carb in most regions, alongside a 0.42 mm reed valve clearance and a 0.5–0.6 mm spark plug gap.

When performing a repair on the 5NX engines, mechanics must handle the YPVS power valve components with specific care; failing to insert the proper set pin before loosening the push rod bolt will routinely cause severe damage to the delicate governor assemblies. Furthermore, it is critical not to use compressed air to spin the bearings dry during overhauls, as this practice will immediately ruin the bearing surfaces. Whether you are dialing in the jetting or completely rebuilding the bottom end, these are the exact numbers required to properly maintain the machine.