2001–2005 Yamaha Raptor 660 YFM660RN/YFM660RNC ATV Service Manual (P/N LIT-11616-14-21)

Yamaha service manual LIT-11616-14-21, with cover code 5LP-28197-E0, covers the 2001–2005 Raptor 660 YFM660RN and YFM660RNC. The specifications distinguish 5LP1 models from the California 5LP3 configuration.

Supplied as one 328-page PDF in English.

• Engine repair: Engine removal, cylinder-head and piston service, crankcase separation, crankshaft installation, and starter one-way clutch and gear inspection.

• Clutch and transmission: Wet-clutch disassembly, gear and shaft inspection, shift-drum and shift-fork checks, and transmission reassembly.

• Carburetor service: Dual Mikuni BSR33 carburetor disassembly and rebuilding, float-height adjustment, fuel-level measurement, and throttle-linkage synchronization checks.

• Cooling system: Radiator inspection, cap pressure testing, thermostat checks, water-pump disassembly, and mechanical-seal replacement.

• Brakes and chassis: Master-cylinder and caliper repair, hydraulic brake bleeding, steering-stem service, ball-joint replacement, and suspension adjustment.

• Electrical diagnosis: DC-C.D.I. ignition fault tracing, starter-motor repair, charging tests, and circuit diagrams for lighting, warning lights, and fan control.

• Periodic maintenance: Valve-clearance and idle-speed adjustment, drive-chain checks, coolant replacement, and the factory inspection and lubrication schedule.

Written primarily for Yamaha dealers and qualified mechanics, this manual assumes an understanding of mechanical principles and machine repair procedures.

Engine Repair and Transmission

Internal engine work includes rocker-arm and camshaft inspection, valve-guide replacement, decompression-system checks, and piston and ring inspection. Timing illustrations support camshaft installation, while crankshaft and balancer sections cover removal, inspection, and reassembly.

The wet-clutch and gearbox sections distinguish friction-plate types and show gear, washer, and circlip arrangements. Wear-limit and clearance tables cover camshaft dimensions, piston-to-cylinder clearances, and valve-stem tolerances. Component-specific torque tables and lubrication charts identify fastener requirements and grease and sealant applications.

Exploded assembly drawings pair numbered components with removal and disassembly job charts. Special-tool references include crankcase separator YU-01135-A and crankshaft installer set YU-90050.

Dual Mikuni Carburetor Service

The carburetor tables distinguish the main jets and pilot air jets for carburetors No. 1 and No. 2, helping keep their components correctly assigned during a rebuild. Needle-valve, diaphragm, and starter-plunger inspections accompany the reassembly and synchronization notes.

Cooling and Lubrication Systems

Water-pump repair extends to the impeller shaft, bearing, oil seal, and mechanical seal, with installer YM-33221 identified. Coolant Flow Diagrams and Oil Flow Diagrams show the coolant connections and dry-sump lubrication routes through the tank, pump, filter, and transmission.

Brakes, Steering and Suspension

Rear-axle service covers bearing and spline inspection plus the axle-nut tightening procedure. The manual warns that direct hammer blows can damage the axle threads and splines.

Ball-joint coverage distinguishes replaceable lower joints from upper-arm assembly replacement. Suspension adjustment covers front spring preload and rear preload, rebound, and compression damping; rear shock procedures address removal, inspection, and assembly replacement.

Follow the manual's support and brake-service precautions; the pressurized rear shock and gas cylinder must not be opened.

Electrical Testing and Wiring

The Ignition System Circuit Diagram and Electric Starting System Circuit Diagram accompany component tests and troubleshooting charts. Starting-circuit coverage explains neutral and clutch interlocks; ignition and charging checks include pickup-coil, rotor-rotation detection-coil, and stator-coil resistance.

The YFM660R Wiring Diagram provides connector layouts and wire-color codes, while Cable Routing drawings locate harnesses, hoses, and control cables. Fault charts address hard starting, poor running, shifting problems, clutch drag, and overheating.

PDF Navigation and Diagram Readability

The page total includes 14 front-matter pages, 312 technical pages, one back cover, and one final wiring-diagram page. Service text is searchable, but labels within wiring drawings and some charts are not; 64 bookmarks reach major sections, with several maintenance links opening on continuation pages. Small wiring labels require zooming for comfortable reading.