🏷️ Basic Information

Make:

Yamaha

Model:

YFM660RNC

Product Type:

Full Service Repair Manual

Chassis Code:

YFM660RNC

👋 Introduction

Category:

High-performance sport ATV

Target Audience:

Enthusiasts seeking a powerful and capable ATV for recreational riding, trails, and moderate off-road use.

Key Competitors:

Honda TRX450R/Foreman, Suzuki LT-Z400/KingQuad, Kawasaki KFX700/Prairie, Polaris Predator/Sportsman.

Engine Type:

Liquid-cooled, DOHC, 4-stroke, 5-valve, single-cylinder engine.

Transmission Type:

5-speed manual with reverse.

Suspension Design:

Independent front suspension (double A-arm) and swingarm rear suspension with adjustable shocks.

Braking System Design:

Hydraulic disc brakes front and rear.

Drive System:

Shaft drive, 2WD.

📋 Manual Details

Model Years Covered:

2001, 2002, 2003, 2004, 2005, 2006

Estimated Pages:

N/A (PDF content varies, typically extensive for full service manuals)

Type:

Service and Repair Manual

Language:

English

Format:

PDF Download

📖 Manual Coverage

Engine:

Detailed procedures for disassembly, inspection, repair, and reassembly of all engine components, including top-end, bottom-end, valve train, cooling system, lubrication system.

Transmission:

Comprehensive coverage of the 5-speed manual transmission, including clutch operation, gear selection, lubrication, and internal component servicing.

Fuel System:

Detailed information on the carburetor system (likely Mikuni), fuel pump, fuel lines, and related components.

Ignition System:

Ignition timing, spark plug specifications, CDI unit, and troubleshooting of the ignition system.

Electrical System:

Wiring diagrams, component testing (stator, regulator/rectifier, battery, starter motor, lighting, instrumentation).

Chassis And Suspension:

Front and rear suspension components (shocks, A-arms, steering components), frame inspection, and wheel bearing maintenance.

Braking System:

Hydraulic disc brake system (front and rear), including caliper overhaul, master cylinder service, pad replacement, and fluid bleeding procedures.

Cooling System:

Radiator service, coolant type and capacity, fan operation, and hose inspection.

Exhaust System:

Muffler, header pipe, and heat shield inspection and service.

Bodywork And Plastics:

Removal and installation of fenders, body panels, seat, and other trim components.

Routine Maintenance:

Oil changes, filter replacements, spark plug checks, chain adjustment and lubrication, air filter cleaning/replacement, brake inspection.

Troubleshooting:

Diagnostic procedures for common performance issues, starting problems, electrical faults, and drivability concerns.

Engine Rebuild:

Complete engine overhaul procedures, including piston replacement, ring installation, cylinder honing, crankshaft inspection, and bearing replacement.

Carburetor Tuning:

Detailed steps for carburetor cleaning, adjustment (idle speed, air-fuel mixture), and jetting recommendations.

Electrical Component Testing:

Methods for testing stator output, regulator/rectifier function, starter motor draw, and battery condition using a multimeter.

Suspension Adjustment And Repair:

Instructions for adjusting suspension settings and replacing worn suspension components.

Brake System Overhaul:

Complete guide to servicing brake calipers, master cylinders, and bleeding the brake system.

Depth:

Comprehensive, covering everything from basic maintenance to full engine and transmission rebuilds. Suitable for both DIY enthusiasts and professional mechanics.

📊 Manual Specifications

Searchable Text:

Likely, depending on the source of the PDF. High-quality manuals are typically text-searchable.

Clarity Of Diagrams:

High. Service manuals rely heavily on clear diagrams and illustrations for repair procedures.

Digital Format:

N/A (PDF is a digital format)

Digital Format:

N/A (PDF is a digital format)

⚙️ Engine Specifications

Engine Type:

4-stroke, liquid-cooled, DOHC, 5-valve, single-cylinder

Displacement:

660 cc

Bore X Stroke:

100.0 mm x 84.0 mm

Compression Ratio:

9.1:1

Carburetor:

Mikuni BSR42, single

Horsepower Estimated:

Approx. 40-45 HP (actual figures vary by region and tuning)

Torque Estimated:

Approx. 38-42 ft-lbs (actual figures vary by region and tuning)

Fuel Delivery:

Carbureted

Fuel Type:

Unleaded gasoline

Fuel Tank Capacity:

2.6 gal (9.8 L)

🔧 Transmission

Type:

5-speed manual with constant mesh, wet multi-disc clutch

Reverse:

Yes

Drive Type:

Shaft drive, 2WD

Final Drive:

O-ring sealed chain

📐 Dimensions

Length:

71.5 in (1815 mm)

Width:

44.1 in (1120 mm)

Height:

42.1 in (1070 mm)

Wheelbase:

50.0 in (1270 mm)

Dry Weight Estimated:

Approx. 412 lbs (187 kg)

Ground Clearance:

4.7 in (119 mm)

🛡️ Safety Features

Atv Safety Considerations:

As an off-road vehicle, safety relies heavily on operator skill, adherence to terrain, proper protective gear (helmet, gloves, boots, eye protection), and following trail guidelines. The manual would emphasize safe operating practices.

Braking:

Front and rear hydraulic disc brakes with hand levers, allowing for precise control.

Handlebars:

Ergonomically designed handlebars for control and stability.

Footwells:

Wide, serrated footpegs for secure footing.

💡 Technology Features

Display Type:

Digital LCD display for speedometer, odometer, trip meter, and warning lights.

Nil:

As a sport ATV of this era, advanced driver-assistance systems (ADAS) are not applicable.

Nil:

No electronic connectivity features are present.

🔧 Maintenance

Engine Oil Change:

Every 20 hours of operation or annually. The manual will specify exact intervals and conditions.

Air Filter Cleaning:

Every 10 hours of operation or as needed depending on riding conditions. The manual will detail cleaning and oiling procedures.

Spark Plug Inspection:

Every 100 hours of operation or annually. The manual will provide gap specifications.

Chain Lubrication And Adjustment:

Every 20 hours of operation or as needed. The manual will specify proper chain slack.

Brake Fluid Flush:

Every 12 months or as recommended in the manual. The manual will specify DOT fluid type.

Engine Oil:

Yamalube 4 (or equivalent) SAE 10W-40 API SG or higher. Manual will specify exact viscosity and API rating.

Engine Oil Capacity:

Approximately 2.4 L (2.5 US qt) with filter change. Manual will confirm.

Coolant:

Yamaha Super Coolant (or equivalent) 50/50 mix of antifreeze and distilled water. Manual will specify type and capacity.

Brake Fluid:

DOT 3 or DOT 4 hydraulic brake fluid. Manual will confirm specific type.

Transmission Oil:

Yamalube Gear Oil (or equivalent) SAE 80 API GL-4. Manual will specify.

Carburetor Performance:

Can be prone to clogging from fuel deposits or dirt, requiring regular cleaning and tuning. Carburetor jetting might need adjustment for altitude or modifications.

Cam Chain Tensioner:

Can become noisy or fail over time, leading to rattling noises from the engine. Replacement is a common maintenance item.

Wheel Bearings:

Can wear out prematurely due to exposure to water, dirt, and stress, requiring periodic inspection and replacement.

Clutch Wear:

Clutch plates can wear out with aggressive riding or improper adjustment, affecting engagement and power delivery.

Stator Failure:

Less common but possible, stator failure can lead to charging system issues and no spark.

📚 Vehicle History

Yamaha Atv Legacy:

Yamaha has a long-standing reputation for producing reliable and performance-oriented ATVs, dating back to the early days of the sport. The YFM series, particularly the 'Raptor' lineage, is a testament to this.

Yfm660R Development:

The YFM660R was Yamaha's flagship sport ATV for several years, known for its powerful engine derived from their utility ATV line, but tuned for performance. It was a significant step up in displacement and power for many riders compared to previous models.

Predecessors:

Preceded by models like the YFM350X Warrior, and paved the way for the fuel-injected YFZ450 and YFZ450R.

Production Period:

2001-2005 (NC designation is often associated with a specific year or minor update within this range, but the core platform spanned these years).

🏆 Awards & Recognition

Industry Perception:

The YFM660R was widely regarded as a powerful and capable sport ATV, earning praise for its engine performance and handling, positioning it as a strong contender in its class during its production run.