2002 Yamaha YFM660F(P) Grizzly 660 Factory Service Manual (P/N 5KM2-AE1)

• Exact model coverage: 2002 Yamaha YFM660F(P), with model code 5KM2 for Canada, 5KM3 for Europe, and 5KM4 for Oceania. The model-label code should be checked before ordering.
• Factory document: Official Yamaha Motor Co., Ltd. service manual, manual number 5KM2-AE1, First Edition May 2001, supplied as a 431-page PDF.
• Engine and V-belt drive repair: Covers engine removal, cylinder-head and valve work, piston and crankshaft inspection, crankcase service, oil-pump and balancer work, plus primary/secondary sheave and centrifugal-clutch disassembly, inspection, and assembly.
• Transmission and shaft-drive service: Details the Low/High/Neutral/Reverse/Park shift mechanism, compact three-axle transmission, middle-gear shim selection and backlash measurement, front differential and gear-motor work, and rear final-drive positioning and gear-lash adjustment.
• Fuel, cooling, brake, and chassis procedures: Includes Mikuni BSR42 carburetor inspection and fuel-level adjustment, radiator/thermostat/water-pump repair, hydraulic brake master-cylinder and caliper rebuilding and bleeding, and steering, suspension, wheel, and brake-disc service.
• Electrical diagnosis and visual references: Provides system-specific fault tracing for ignition, electric starting, charging, lighting, signals, cooling, and 2WD/4WD selection, supported by circuit diagrams and a complete regional wiring diagram.
• Specifications and special tools: Supplies periodic maintenance and lubrication intervals, component torque tables, fluid data, inspection limits, clearances, adjustment data, electrical test values, cable routing, and Yamaha special-tool numbers for the covered work.

Yamaha produced this manual primarily for its dealers and qualified mechanics. It assumes the user already understands basic mechanical principles and machine-repair procedures. Removal and disassembly sections use exploded views, numbered job charts, and illustrated step-by-step supplements, making this a workshop-level publication rather than an owner’s maintenance guide.

Engine, V-Belt Drive, and Transmission

The engine chapters extend from routine checks into major repair. They address rocker arms, the camshaft and decompression system, timing-chain components, cylinder-head inspection, valve and valve-guide service, piston-ring and cylinder checks, crankcase separation, crankshaft and connecting-rod inspection, and oil-pump, relief-valve, and oil-strainer work. Recoil starter and AC magneto service are included as well.

The V-belt automatic drive receives its own removal, inspection, and assembly coverage for the primary and secondary sheaves and wet centrifugal clutch. Internal transmission work includes the shift forks, shift cam, drive axle, secondary shaft, reverse chain, and middle drive and driven gears. The feature section also explains how the chain-driven reverse arrangement creates the compact three-axle layout and how the Park mechanism locks the drive axle.

2WD/4WD Drivetrain and Chassis

The front-drive section explains power flow in 2WD, 4WD, and 4WD differential-lock modes, including gear-motor operation and the differential-lock standby logic. Factory repair procedures cover front constant-velocity joints, the universal joint, differential ring gear, gear-lash measurement, and operational checks. At the rear, the manual addresses the constant-velocity joint, drive shaft, final-drive roller bearing, pinion/ring-gear positioning, shim selection, and final gear-lash adjustment.

Two cautions define the repair scope clearly. Yamaha treats the internal differential gear set as a factory-assembled unit and warns that dismantling it can cause the unit to malfunction. The drivetrain troubleshooting section also warns that insufficient gear lash after reassembly is highly destructive to the gear teeth.

Chassis repair includes front and rear brake pads, master cylinders and calipers, hydraulic bleeding, wheel hubs and discs, the steering stem and bearing retainer, tie rods, steering knuckles and ball joints, front arms, rear arms, stabilizer, and shock absorbers.

Diagnostics, Diagrams, and Service Data

Electrical troubleshooting is organized by system and uses continuity, resistance, voltage, and component checks with the specified test equipment. A separate troubleshooting chapter covers hard starting, poor idle or high-speed performance, drivetrain noise, shifting and clutch faults, overheating, weak braking, shock-absorber problems, unstable handling, and lighting faults.

Named visual references include the coolant-flow diagrams, oil-flow diagrams, cable-routing views, ignition-system circuit diagram, 2WD/4WD selecting-system circuit diagram, and the full YFM660F(P) 2002 wiring diagram. The wiring information identifies the Europe/Oceania horn circuit separately.

The special-tool section lists regional equivalents rather than generic tool descriptions alone. Examples include the crankcase separating tool YU-01135-A / 90890-01135, gear-lash measurement tool YM-01467 / 90890-01467, sheave spring compressor YM-04134 / 90890-04134, and pocket tester YU-03112 / 90890-03112. Hot cooling-system pressure, hydraulic brake work, heavy engine/drivetrain assemblies, and the possibility of shaft-drive lockup from damaged gear teeth all require the factory precautions and appropriate workshop equipment.