The Yamaha YFZ450 S Quad, produced from 2004 to 2009, represents a pinnacle in high-performance sport ATV engineering. Renowned for its powerful liquid-cooled, 4-stroke engine and agile chassis, this model has consistently been a favorite among enthusiasts and competitive riders. Its design prioritizes aggressive handling and responsive power delivery, making it suitable for demanding off-road conditions and racing circuits. The legacy in ATV manufacturing is evident in the YFZ450 S's robust construction and performance-oriented features, establishing it as a formidable competitor in its segment. This comprehensive service manual provides factory-level technical information essential for the maintenance, diagnosis, and repair of your Yamaha YFZ450 S Quad. Covering all major systems, including the engine, drivetrain, suspension, brakes, and electrical components, this 355-page English-language guide offers step-by-step procedures, detailed troubleshooting flowcharts, and critical specifications. Whether you are performing routine maintenance, complex repairs, or restoration, this manual is an indispensable resource for owners and technicians seeking to keep their ATV in optimal condition. 🏷️ Basic Information Identification Make: Yamaha Model: YFZ450 S Quad Vehicle Type: ATV (All-Terrain Vehicle) Model Years Covered: 2004, 2005, 2006, 2007, 2008, 2009 👋 Introduction Market Position Segment: Performance Sport ATV Target Audience: Enthusiasts, Racers, Mechanics, Owners undertaking DIY repairs Competitive Analysis Competitors: Honda TRX450R, Suzuki LT-R450, Bombardier DS450 Key Features Vehicle Highlight: High-performance sport ATV known for its powerful engine and agile handling. Manual Value Proposition: Provides expert-level technical guidance to maintain, diagnose, and repair the YFZ450 S efficiently and effectively. 📋 Manual Details Coverage Areas Primary Coverage: Factory Service Repair Secondary Coverage: Maintenance, Diagnostics, Rebuild, Restoration Page Count Total Pages: 355 Page Quality: High Quality Manual Type Type: Service Manual / Repair Manual Language Language: English Format Delivery Format: Instant Download PDF Software Requirements: Adobe PDF Reader or compatible, WinRAR (if archived) Printing Capability: Printable with no restrictions 📖 Manual Coverage Systems Covered Engine: Complete Engine Overhaul, Rebuild, Diagnostics, Tuning Cooling System: Radiator, Fan, Coolant, Hoses, Pump Fuel System: Carburetor Service, Jetting, Fuel Lines, Filter Drivetrain: Clutch, Transmission, Final Drive, Chain Chassis: Frame, Suspension (Front & Rear), Steering, Swingarm Electrical: Ignition System, Lighting, Battery, CDI, Wiring Harnesses Brakes: Front & Rear Brake Systems, Calipers, Rotors, Master Cylinders, Lines Bodywork: Body Panels, Plastics, Seat, Handlebars Procedures Included Maintenance: Scheduled Maintenance, Lubrication, Filter Changes, Adjustments Troubleshooting: Diagnostic Flowcharts, Common Issues, Symptom Analysis Repair: Step-by-Step Repair Procedures for all covered systems Rebuild: Complete Engine and Component Rebuild Instructions Restoration: Guidance for bringing the ATV back to original specifications Technical Depth Depth: Comprehensive Factory-Level Technical Information Diagnostics: Detailed Diagnostic Procedures and Troubleshooting Guides Illustrations: Detailed Illustrations and Diagrams for clarity 📊 Manual Specifications File Format Format: PDF Searchability: Likely text-searchable PDF (typical for factory manuals) Print Quality Quality Description: High-resolution, clear and legible Binding Type Binding: Digital (Downloadable PDF), Not physically bound Paper Type Paper Type Description: N/A (Digital Format) ⚙️ Engine Specifications Primary Engine Engine Type: Liquid-cooled, 4-stroke, DOHC, 5-valve, Single Cylinder Displacement: 449 cc Bore X Stroke: 95.0 mm x 63.4 mm Compression Ratio: 11.4:1 (Typical, check manual for exact) Performance Horsepower: Approximately 40-45 HP (Varies by model year and tuning, check manual) Torque: Estimated 40 Nm (Check manual for exact) Fuel System Carburetor Type: Mikuni BSR37 (Pilot jet, main jet, needle, and jet needle specifications covered in manual) Fuel Type: Unleaded gasoline (Regular grade, typically 87 octane or higher) Ignition System Ignition Type: TCI (Transistor Controlled Ignition) Cooling System Type: Forced air cooling with radiator Lubrication Type: Wet sump 🔧 Transmission Standard Transmission Type: Constant mesh 5-speed Clutch Type: Wet, multiple-disc Final Drive: O-ring sealed chain Features Reverse: No 📐 Dimensions Exterior Length: Approx. 1,830 mm (72.0 in) Width: Approx. 1,215 mm (47.8 in) Height: Approx. 1,075 mm (42.3 in) Wheelbase: Approx. 1,270 mm (50.0 in) Weights Dry Weight: Approx. 170 kg (375 lbs) Fuel Capacity: Approx. 10.0 L (2.6 US gal) Oil Capacity: Approx. 1.4 L (1.5 US qt) for engine/transmission combined (check manual) Suspension Front Suspension Type: Independent double wishbone with adjustable shocks Rear Suspension Type: Swingarm with adjustable shock Tires Front Tire Size: AT21x7R-10 (Manual will specify ply rating and brand recommendations) Rear Tire Size: AT20x10R-9 (Manual will specify ply rating and brand recommendations) Brakes Front Brake Type: Dual hydraulic disc Rear Brake Type: Single hydraulic disc 🛡️ Safety Features Ratings Atv Safety Standards: Adheres to relevant industry safety standards (ANSI, etc., manual may reference) Active Features Throttle Limiter: Typically none for performance ATVs; emphasis on rider skill. Passive Features Handlebar Design: Standard ATV handlebars with handguards (often aftermarket) 💡 Technology Features Infotainment Display: Digital LCD instrument cluster (speedometer, odometer, trip meter, clock, neutral indicator). Driver Assistance Features: None (This is a sport ATV focused on rider control and mechanical performance). 🔧 Maintenance Service Intervals Oil Change Interval: Refer to manual: typically every 10-15 operating hours or annually, whichever comes first. Air Filter Cleaning: Refer to...