Yamaha Grizzly 660 YFM660FS ATV Service Manual Set, 2004–2005 (P/N LIT-11616-17-14)

Yamaha specifies using the FS supplement together with the FR supplement and FP service manual. All three are included, pairing the model-specific revisions with the detailed base repair procedures.

PDF Search, Bookmarks and Wiring Detail

Search and diagram access: Text search is available in the FS supplement and base manual; the FR supplement has no searchable text. Embedded bookmarks provide access to all three publications and their service sections. Small wiring-diagram labels require enlargement.

The set is supplied as one printable, English-language, 478-page PDF. The publication totals above include 31 cover and introductory pages, three back covers, and two full wiring-diagram sheets.

Engine, Drivetrain and Electrical Service

The following selected service topics highlight the repair coverage; additional sections include recoil-starter service and spark-arrester cleaning.

• Engine repair: Engine removal and installation, cylinder-head service, valve-train inspection, and cylinder, piston and crankshaft work.

• Transmission and clutch: Primary and secondary sheave disassembly, V-belt inspection, centrifugal-clutch checks, and internal transmission removal and assembly.

• Drivetrain service: Front constant-velocity joints, differential gear, rear final drive and drive shaft, with gear-lash measurement and shim-selection procedures.

• Carburetor setup: Disassembly, component inspection, float-height and fuel-level adjustment, plus jetting, idle-speed and intake-vacuum specifications.

• Cooling system: Radiator inspection, cap-pressure testing, thermostat checks, water-pump disassembly and seal installation, with coolant-flow diagrams.

• Brakes and chassis: Brake-pad replacement, master-cylinder and caliper service, hydraulic bleeding, wheel-bearing replacement, steering checks and suspension inspection.

• Electrical diagnosis: Ignition, charging, starting, lighting, signal and 2WD/4WD troubleshooting, with FS override-switch continuity information and model-specific wiring diagrams.

Written primarily for Yamaha dealers and qualified mechanics, these manuals assume a basic understanding of mechanical principles and machine repair.

Internal Engine and Belt-Drive Repair

Step-by-step procedures cover crankcase separation and crankshaft installation, with valve-seat and guide measurements, piston-ring inspection, decompression-system checks and oil-pump clearances. Engine and chassis torque tables identify the fasteners associated with each assembly.

The transmission section follows the shift forks, shift cam, shafts and reverse-drive chain through inspection and reassembly. Sheave service identifies the required holding and spring-compression tools, including sheave holder YU-01880 and spring compressor YM-04134.

Carburetor Inspection and Cooling-System Work

Carburetor coverage includes the needle valve and seat, piston-valve diaphragm, coasting enricher and jet passages. These checks connect component condition with fuel-level setting and running-condition diagnosis.

Coolant-flow and oil-flow diagrams show the relevant passages and connections. Water-pump instructions address the mechanical seal, oil seal, bearing and impeller alignment, extending the cooling coverage beyond hose and coolant replacement.

Differential, Final Drive and Chassis Details

The driveline sections provide middle-gear and final-drive shim calculations, differential gear-lash adjustment and differential-preload checks. The factory-assembled internal differential unit is not intended to be dismantled.

The middle-driven-shaft instructions warn that direct hydraulic-press loading can damage the shaft threads. Drivetrain troubleshooting also identifies insufficient gear lash as a cause of gear-tooth damage.

Chassis references distinguish wheel-hub fasteners, steering-knuckle and rear-knuckle bearings, and brake hydraulic components. Suspension spring data, inspection limits and assembly drawings support the related checks.

Circuit Testing and Cable Routing

System-specific troubleshooting charts combine component checks, resistance tests and wiring inspection. These references help distinguish a wiring problem from a failed component, including pickup-coil, charging-coil, starter-relay and drive-selection faults.

The YFM660FS and YFM660FP wiring diagrams are supported by signal-system and 2WD/4WD selecting-system circuit diagrams. The FS supplement also documents the differential-lock override display and associated switch connections.

Cable routing is documented separately from the electrical schematics, which is useful after chassis, handlebar, fuel-system or electrical components have been disturbed. The layouts identify hose paths, harness guides and fastening points relevant to clearance and protection from pinching.

Service work involving the front drivetrain, wheel hubs, ignition or charging circuits should be carried out with the ATV properly secured and the applicable electrical and mechanical safety practices in place. Use the factory procedures together with appropriate shop equipment and professional judgment.

Carburetor and Pickup-Coil Specification Examples

Carburetor reference data lists a float height of 13 mm and a fuel level 4.5 mm above the float-chamber mating surface. The carburetion chapter includes the corresponding measurement and adjustment procedures.

For the YFM660FS ignition system, the supplement specifies pickup-coil resistance of 459–561 Ω at 20 °C (68 °F), measured between the White/Red and White/Green leads.