2001–2006 Yamaha Raptor 660 YFM660R ATV Service & Repair Manual

This Yamaha service manual covers the 2001–2006 Raptor 660 YFM660R, with specifications for model codes 5LP1 and 5LP3. Its nine chapters cover machine identification, scheduled maintenance, mechanical repair and system troubleshooting.

• Engine repair: Engine removal, cylinder-head and valve-train service, piston inspection, crankcase separation, crankshaft installation and balancer alignment.

• Clutch and transmission: Clutch-housing and plate inspection, shift-shaft service, gear and shift-fork checks, and transmission disassembly and reassembly.

• Carburetion: Twin Mikuni BSR33 carburetor removal and disassembly, diaphragm and jet inspection, float-height measurement and fuel-level adjustment.

• Cooling and lubrication: Radiator and cap testing, thermostat inspection, water-pump seal replacement, oil-pump checks, and coolant and oil flow diagrams.

• Brakes and chassis: Hydraulic brake bleeding, caliper and master-cylinder service, wheel-bearing replacement, steering-knuckle inspection, toe-in adjustment and suspension service.

• Electrical troubleshooting: Ignition, starting, charging, lighting and cooling-fan circuit tests, starter-motor service, wiring diagrams and cable-routing drawings.

This manual is suited to mechanics comfortable with engine teardown, precision measurements and the specialized service tools specified for the work.

Engine, Clutch and Gearbox Work

Internal engine inspection: The engine chapter covers valve timing, valve-guide replacement and valve-seat checks, piston-ring clearances, cylinder wear and crankshaft measurements. Exploded views and job charts accompany disassembly sections, while torque tables and illustrated tightening sequences support reassembly.

Clutch and shifting: Inspection procedures distinguish friction-plate wear, clutch-plate warpage and clutch-housing damage. Transmission coverage extends to the main and drive axles, reverse gears, shift drum and shift forks, with checks for gear engagement and free movement before crankcase assembly.

The tool lists identify equipment such as crankcase separator YU-01135-A and crankshaft installer set YU-90050. The crankcase section warns against striking mating surfaces during separation, which can damage the sealing faces.

Carburetor Adjustment and Cooling-System Service

Fuel delivery: Carburetor service includes needle-valve and seat inspection, piston-valve diaphragm checks and separate jet specifications for the two carburetors. The fuel-level procedure identifies gauge YM-01312-A; reassembly notes also address throttle-valve movement and synchronization.

Cooling and oil circulation: Radiator-cap pressure testing, thermostat opening checks and water-pump disassembly are supported by coolant flow diagrams. Oil flow diagrams trace the tank, pump, filter and internal passages, alongside oil-pump rotor-clearance checks.

Brakes, Steering and Suspension

The chassis chapter covers brake calipers and master cylinders, steering-stem bearings, tie-rods, steering knuckles, swingarm bearings and rear suspension linkage. The rear-axle section includes its specific ring-nut tightening procedure.

Rear shock coverage: Procedures cover removal, inspection, spring preload and damping adjustment. A leaking or damaged rear shock is replaced as an assembly; the pressurized shock and gas cylinder are not intended to be opened for internal repair.

The brake section explains that unsuitable cleaning solvents can swell and distort caliper seals. Follow the manual's safety precautions for supporting the ATV, servicing hydraulic brakes and handling the pressurized cooling system and rear shock.

Electrical Tests and Fault Tracing

Ignition and electric-starting circuit diagrams accompany checks for coils, switches, relays and wiring connections. The starting-circuit explanation shows how the neutral and clutch switches affect starter operation, helping distinguish an interlock fault from a starter-motor problem.

Starter-motor inspection includes the brushes, commutator and armature. Mechanical starter one-way clutch checks appear in the AC magneto section.

Charging, lighting, indicator and cooling-fan tests provide their own diagnostic paths; symptom guides address hard starting, clutch slipping or dragging, shifting trouble and overheating.

Valve, Head-Bolt and Coolant Specification Preview

Cold intake valve clearance is specified at 0.10–0.15 mm. For cylinder-head installation, the M9 bolts have a final torque of 38 Nm (27 ft-lb) within the illustrated two-stage tightening sequence.

Cooling specifications list a radiator capacity of 1.3 L including all coolant routes, with the coolant reservoir specified separately.

Searchable Service Text and PDF Bookmarks

Search, navigation and diagram detail: Service text is searchable, while some chart text and labels within wiring diagrams are not. Embedded bookmarks cover all nine chapters and selected procedures, although some open partway through a procedure. Small wiring and connector labels require zooming.

One printable, English-language 325-page PDF contains the manual, including 12 preliminary pages of instructions, symbols and contents, plus the final wiring-diagram page.