Yamaha Grizzly 660 ATV 2002–2008 Service Manual (P/N 90890-01309)

• Covers the 2002–2008 Yamaha Grizzly 660 (YFM660F) equipped with the 660cc liquid-cooled 4-stroke SOHC engine and V-belt automatic transmission
• Official Yamaha publication P/N 90890-01309
• Features over 80 mechanical exploded-view diagrams
• Includes comprehensive maintenance torque tables for all critical engine and chassis fasteners
• Spans 466 pages of dedicated factory reference material, detailing specialized 4WD and differential lock system diagnostics
• Outlines step-by-step procedures for adjusting the valve clearance, bleeding the hydraulic brake system, replacing the V-belt, rebuilding the Mikuni BSR42 carburetor, and servicing the CV joints and AC magneto
• Contains essential wiring diagrams, detailed circuit diagrams, comprehensive cable routing views, specific oil flow diagrams, coolant flow charts, and visual job instruction charts

Operational and Service Documentation

This PDF factory publication breaks down the drivetrain, chassis, and electrical systems of the 2002–2008 Yamaha Grizzly 660. It moves from basic machine identification right into heavy component analysis to help you execute a proper repair. You get a complete breakdown of the 5KM-series engine architecture and the 3-axle transmission mechanism. Need to trace a fluid issue? The manual maps out exact lubrication points, coolant flow paths, and detailed oil flow diagrams. It also covers the specific parking-position shift mechanism introduced for this model year. By following the detailed teardown sequences, DIYers can bypass expensive dealership labor for intricate jobs like primary and secondary sheave overhauls or steering knuckle replacements. Beyond basic periodic maintenance, the chapters walk you through complex electrical circuit troubleshooting and high-level internal engine evaluations to properly fix the ATV. Working on ATV drivetrains carries inherent physical risks. Always follow the documented factory safety procedures before lifting the vehicle or dismantling high-tension components.

Specification and Reference Highlights

Having access to exact factory formulas and tolerances eliminates bench-time hesitation, significantly increasing turnaround efficiency for heavy driveline services. This manual provides the hard technical specifications required for serious bench work, covering critical clearances, fluid capacities, and fastener torque ratings. For example, cylinder head bolt torque is strictly documented at 38 Nm. Critical spark plug gap settings are listed at 0.8–0.9 mm. You will find exact fluid requirements, including a 1.8-liter coolant system capacity and a 1.9-liter engine oil specification for periodic changes. Precision matters when rebuilding the drive system. The documentation details exact differential gear backlash settings, specified right at 0.05–0.25 mm, so you can lock in factory-standard tolerances across the entire YFM660F series.

When performing a drive line repair, technicians must be aware that the middle driven shaft bearing retainer features left-hand threads, which are easily stripped if turned the wrong way. Furthermore, achieving the exact 4WD gear motor alignment before installing the differential gear assembly is critical; a slight shift can misalign the indicator light display and completely prevent the differential lock from activating.