1989-1991 Yamaha YFM250 Moto 4 ATV Service Manual

Inside the 1989–1991 Yamaha YFM250 Moto 4 Service Manual

• Built for owners and professional workshops maintaining the 1989–1991 Yamaha YFM250 Moto 4 all-terrain vehicle
• Official OEM publication LIT-11616-06-62, first edition August 1988
• Contains dozens of technical diagrams, maintenance specification tables, and exploded-view illustrations for engine and chassis systems
• Downloads to your account within seconds of checkout
• Indexed PDF search covers every chapter and appendix
• Re-download the file any time, no expiration
• This 1988 first edition is the primary reference documentation for the 3GH model series

Procedural and Technical Walkthrough

This 1989–1991 Yamaha YFM250 Moto 4 service publication outlines maintenance for the air-cooled 229.6 cc SOHC engine and five-speed transmission. The first section documents machine identification, serial number locations, and essential service tool lists, followed by a detailed periodic maintenance schedule covering spark plug inspection, valve clearance verification, and lubrication intervals. Subsequent chapters detail engine removal, disassembly, and overhaul procedures including piston, cylinder, and clutch inspection metrics. The drivetrain documentation provides guidance on shaft drive maintenance, gear lash measurement, and steering system inspection.

Chassis and Electrical Reference Data

Specifications are provided for the front and rear drum/disc braking systems, including cable free-play adjustments and shoe thickness wear limits. Electrical system data includes circuit diagrams, starter relay resistance, magneto pickup coil thresholds, and charging system output values. The 1989–1991 Yamaha YFM250 Moto 4 chassis section lists torque specifications for frame and suspension components, including the swingarm and steering column. Valve clearance for the intake is listed at 0.05–0.09 mm in the cylinder head specification table. The engine idle speed for the 1989–1991 Yamaha YFM250 Moto 4 is documented at 1,450–1,550 r/min. Magneto pickup coil resistance is specified at 180–220 ohms at 20°C in the electrical specification section.

Note: All service data shown here is for reference only — qualified technicians and the original OEM documentation remain the authoritative source for any hands-on work. How factory workshop documentation is structured provides further context. An official 112-page Yamaha OEM workshop manual covering the 1989–1991 Yamaha YFM250 Moto 4, documenting engine, chassis, electrical, and drive-train specifications for the 3GH-series build.