2004–2007 Yamaha Rhino 660 ATV Service Manual (P/N 5UG-F8197-10, 5UG-F8197-11)

• Model-specific coverage: Yamaha Rhino 660 YXR660FAS with model code 5UG1; YXR660FAT with model codes 5UG4 and 5UG8; and the YXR66FAV 2006 supplement for US codes 5UG9/5UGB/5UGF, Canadian codes 5UGA/5UGC/5UGG, European codes 5UGD/5UGH, and Oceania code 5UGE. The PDF does not contain a 2007 supplement.
• 506-page PDF set: 413-page YXR660FAS base service manual (internal Manual No. 5UG-F8197-10), 39-page YXR660FAT supplement (internal Manual No. 5UG-F8197-11), and 54-page YXR66FAV 2006 supplement.
• Engine repair coverage runs from removal and installation through the camshaft, cylinder head, valves, piston, crankcase, crankshaft, balancer, oil pump, internal transmission, and final assembly checks.
• V-belt and shaft-drive procedures address the primary and secondary sheaves, wet centrifugal clutch, middle gear, front and rear CV joints, differential and final-drive cases, shim selection, gear-lash measurement, and 2WD/4WD gear-motor operation.
• Chassis work covers front dual-disc and rear single-disc brake bleeding and caliper/master-cylinder repair, the self-adjusting parking brake, rack-and-pinion steering, wheel hubs, tie-rods and knuckles, double-wishbone arms, shock absorbers, stabilizer, enclosure, and cargo bed.
• Cooling and fuel-system service covers the radiator and reservoir, water-pump disassembly and reassembly, oil-cooler inspection, fuel-pump operation, the fuel tank, BSR42 carburetor overhaul, and fuel-level adjustment.
• Electrical and reference material supplies model-specific wiring diagrams, circuit diagrams and fault-isolation charts, coolant- and oil-flow diagrams, cable-routing layouts, exploded views, job instruction charts, torque tables, capacities, wear limits, clearances, and electrical test data.

Engine and Drivetrain Repair Depth

This is workshop-level material for the liquid-cooled 660 cc single-cylinder SOHC engine, BSR42 carburetor, V-belt automatic transmission, shaft final drive, and On-Command 2WD/4WD system. Its repair depth and reliance on pullers, holding fixtures, a press, a dial indicator, and electrical test equipment make it best suited to professional technicians and experienced owners with established shop skills.

The periodic section covers valve-clearance and timing-chain adjustment, ignition-timing and compression tests, V-belt inspection, toe-in, brake bleeding, and battery charging. The engine chapters go beyond those service tasks. They cover the decompression system, timing chain and tensioner, valve seats and guides, piston and rings, starter clutch, A.C. magneto, balancer gears, oil pump and relief valve, crankcase separation, crankshaft installation, shift forks, shift drum, and drive axle. Removal and disassembly sections use exploded diagrams and ordered job charts, backed by component-specific tightening data, inspection limits, lubrication points, and replacement criteria.

Driveline repair is similarly detailed. The middle-gear section covers drive and driven shaft removal, pinion inspection, shim selection, and backlash measurement. Separate front and rear chapters handle universal joints, CV joints, the differential gear motor, final-drive bearings, ring-and-pinion positioning, lash adjustment, reassembly, and operational checks. Brake coverage extends from pad replacement to master-cylinder and caliper disassembly, seal replacement, reassembly, installation, and hydraulic bleeding.

Variant Updates and Diagnostics

The YXR660FAT supplement is not a duplicate of the base book. It revises transmission, carburetor, chassis, electrical, torque, and cable-routing data, then adds changed air-filter, parking-brake, exhaust/air-duct, carburetor-joint, body-panel, cargo-bed, and seat-belt procedures. The YXR66FAV 2006 supplement separates standard and special-edition equipment where required, including indicator displays, steel versus cast wheels, lighting circuits, hub hardware, front-arm and stabilizer details, front guard and skid plates, the engine cooling fan/A.C. magneto area, and the oil cooler.

Electrical diagnosis is organized by system rather than as one undifferentiated schematic. Named coverage includes ignition, electric starting, charging, lighting, signaling, cooling-fan control, 2WD/4WD selection, and carburetor heating. A separate troubleshooting chapter traces starting and running complaints through fuel, electrical, and compression causes, then covers drivetrain, shifting, clutch, overheating, braking, shock, handling, and lighting faults. Visual references include the YXR660FAS, YXR660FAT, and YXR66FAV model-specific wiring diagrams, the 2WD/4WD selecting-system circuit, coolant-flow diagrams, and oil-flow diagrams.

Tools, Limits, and Repair Cautions

The special-tool index pairs US/Canadian numbers with their international 90890-series equivalents. Examples tied to major work include the sheave spring compressor YM-04134/90890-04134, gear-lash measurement tool YM-01467/90890-01467, bearing-retainer wrench YM-04128/90890-04128, and pulse ignition spark checker YM-34487/90890-06754.

The front differential gear unit is factory-matched, and the manual warns that splitting it will cause malfunction; service instead centers on the permitted gearcase, gear-motor, positioning, and lash procedures. Too little gear lash can rapidly destroy the gear teeth, while disturbing the indexed shift-fork/gear-motor position can leave the indicator out of sync and prevent 2WD or differential-lock engagement.

Because the repair work includes brake hydraulics, a compressed secondary-sheave spring, engine removal, and heavy drivetrain parts, use suitable support and lifting equipment together with the specified service tools. Work beyond the technician's training or shop equipment should be referred to a qualified repair facility.