Yamaha YZ250A and YZ250WRA 1990 Owner's Service Manual (P/N LIT-11626-07-06)

• 85-page official OEM publication (P/N LIT-11626-07-06, first edition July 1989), including the critical 1990 YZ250WRA correction sticker data.
• Covers exact technical specifications, detailed engine assembly limits, and chassis teardown data for these 250cc motocross models.
• Contains 47 exploded-view diagrams, 3 electrical component charts, and 4 specialized torque-sequence tables.

Complete Engine and Chassis Teardown Blueprint

When you have a vintage two-stroke torn down on the bench, guesswork doesn't cut it. This factory manual cuts straight to the chase, delivering the exact mechanical data required for routine maintenance or a full bottom-end rebuild. The content is logically broken down into general info, engine internals, chassis assemblies, and appendices. Because this manual is delivered as an instant download, you can pull up these exact specifications on your shop tablet or print the pages you need right at your workbench.

For the engine, the reference maps out the fuel tank and radiator assembly, carburetor and reed valve adjustments, and the complete cylinder head and piston maintenance sequence. Further in, you'll find exploded views of the clutch housing, kick axle, and shifting components. The chassis sections provide precise reference points for front and rear wheel service, brake system bleeding, fork oil levels, and steering head bearing replacement.

Technical Specifications & Assembly Data

Getting the numbers right is what separates a reliable build from a blown engine. The specifications section completely removes the guesswork by listing exact factory torque values. This includes primary fasteners like cylinder head nuts at 30 Nm (22 ft-lb) and clutch boss nuts at 75 Nm (54 ft-lb).

Electrical diagnostics are clearly mapped out. You'll find CDI pinouts and charging coil resistance values, alongside the YZ250WRA-specific pickup coil resistance of 104–156 ohms. Engine timing data is firmly established for the YZ250A at 13°/8,500 rpm.

Working on high-output motocross bikes carries inherent physical risks. Always cross-reference this technical data carefully, use the proper tools, and consult a certified technician before tackling major mechanical overhauls if you are unsure about an assembly procedure. If you'd like a better idea of how this type of factory data is organized, take a look at how factory workshop documentation is structured to understand the technical depth provided in this release.