🏷️ Basic Information Identification Make: Yamaha Model: YFZ450S Year: 2004 Vehicle Type: ATV (All-Terrain Vehicle) / Quad Codes Yamaha Publication Number: LIT-11616-17-11 👋 Introduction Market Position Market Segment: High-performance sport ATV, positioned for racing and aggressive recreational riding. Competitive Analysis Competitors: Honda TRX450R, Suzuki LT-R450, Kawasaki KFX450R. Key Features Vehicle Highlights: Known for its potent 5-valve titanium cylinder head engine, lightweight design, and aggressive styling, the YFZ450S was a dominant force in its class. Manual Value Manual Benefit: Provides essential information for maintaining peak performance, diagnosing issues, and executing repairs on the 2004 Yamaha YFZ450S. 📋 Manual Details Coverage Areas Coverage Scope: Comprehensive service and repair for the 2004 Yamaha YFZ450S ATV. Page Count Number Of Pages: 355 Manual Type Type: Official Service Repair Shop Manual Language Language: English Format File Format: PDF 📖 Manual Coverage Systems Covered Engine Management: Combustion specs, fuel system, lubrication, cooling, intake, exhaust, spark plug, CDI, ignition coil. Powertrain: Transmission, gearbox, drive train, clutch (including charging clutch), con rod, crankshaft, camshaft, cylinder, piston, rings, cams, primary reduction gear, shaft. Chassis And Body: Wheel and steering system, frame, sub-frame, body and fender assembly, handlebars, seat, fuel tank, oil tank, skid plate, decals, plastic body panels. Electrical: Electrical system, starter, stator, magneto, flywheel, battery, rectifier, charge system, switches (start, kill, switch, button), wiring diagram. Brakes And Suspension: Brakes, brake pads, rotor, hydraulic system, suspension (front and rear), struts, swingarm, axle, boots. Procedures Included Diagnostic And Troubleshooting: Advanced level troubleshooting, error code analysis, problem identification and resolution for various systems. Maintenance: Routine maintenance, lubrication schedules, fluid changes (oil, coolant), filter replacement, air filter cleaning. Repair And Overhaul: Engine installation/removal, complete engine overhaul, transmission rebuild, carburetor adjustment/rebuild (including jetting), clutch service, brake system repair, steering system overhaul. Component Replacement: Replacement of pistons, rings, gaskets, bearings (wheel, gearbox), sprockets, chains, lamps, bulbs, throttle cables, water pump, starter motor, kickstart mechanism, thermostat. Technical Depth Depth: Detailed step-by-step instructions, torque specifications, critical notes, cautions, and warnings for all repair procedures, suitable for professional mechanics and advanced DIY enthusiasts. 📊 Manual Specifications File Format Quality: High-resolution PDF, bookmarking for easy navigation of chapters. Printability: Printable pages for convenient workshop use. Binding Type Binding: N/A (Digital Download - PDF) Paper Type Paper Type: N/A (Digital Download - PDF) ⚙️ Engine Specifications Primary Engine Engine Type: 4-stroke, liquid-cooled, DOHC, 5-valve, Titanium cylinder head Displacement: 449 cc Bore X Stroke: 95.0 mm x 63.1 mm Compression Ratio: 11.4:1 Performance Horsepower Estimate: Approx. 45-50 HP (at crankshaft, manufacturer's estimate) Torque Estimate: Approx. 30-32 lb-ft (manufacturer's estimate) Fuel System Carburetion: Keihin 37mm flat-slide carburetor with TPS (Throttle Position Sensor) Fuel Type: Unleaded gasoline, minimum 87 octane Lubrication Oil Type: Yamalube 4 (or equivalent) 10W-40 API SG or higher Oil Capacity: 1.90 L (2.01 US qt) with oil filter change Cooling System Coolant Type: Permanent type anti-freeze coolant (50/50 mix with distilled water) Coolant Capacity: 1.3 L (1.37 US qt) Ignition Ignition System: CDI (Capacitor Discharge Ignition) Starting System Starter: Electric starter and a mechanical decompression system/kickstart lever. 🔧 Transmission Standard Transmission Type: Constant mesh 5-speed sequential Clutch Type: Wet, multiple-disc, cable operated, assisted clutch Features Gear Ratios: 1st: 2.438 (29/10), 2nd: 1.765 (30/17), 3rd: 1.333 (28/21), 4th: 1.111 (20/18), 5th: 0.917 (22/20) Final Drive: O-ring sealed chain Lubrication Gear Oil Type: Yamalube 4 (or equivalent) 10W-40 API SG or higher Gear Oil Capacity: 0.55 L (0.58 US qt) 📐 Dimensions Exterior Overall Length: 1830 mm (72.0 in) Overall Width: 1230 mm (48.4 in) Overall Height: 1040 mm (40.9 in) Seat Height: 800 mm (31.5 in) Wheelbase: 1260 mm (49.6 in) Weights Dry Weight: 177 kg (390 lbs) Fuel Tank Capacity: 9.0 L (2.4 US gal) Oil Tank Capacity: 3.2 L (3.38 US qt) 🛡️ Safety Features Ratings Safety Features Overview: Designed for experienced riders, emphasizes rider skill and responsible operation; lacks electronic driver aids common in modern vehicles. Active Features Braking System: Hydraulic disc brakes front and rear with braided stainless steel lines for enhanced feel and performance. Passive Features Chassis Design: Strong, lightweight aluminum frame and sub-frame for stability and handling. Control Features: Wide handlebars for leverage, ergonomic seating position. 💡 Technology Features Infotainment Infotainment System: N/A (Performance-focused ATV with minimal creature comforts). Driver Assistance Driver Assistance Systems: N/A Engine Technology Cylinder Head Design: Advanced 5-valve titanium cylinder head design for improved airflow and performance. Throttle Sensor: Includes a Throttle Position Sensor (TPS) for more precise fuel delivery and engine management. 🔧 Maintenance Service Intervals Engine Oil Change: Every 10 hours of operation or monthly, whichever comes first (severe use); Every 20 hours or 3 months (normal use). Air Filter Cleaning: Clean every 5-10 hours or more frequently in dusty conditions. Spark Plug Inspection: Inspect every 10 hours of operation. Chain Lubrication Adjustment: Lubricate every 10 hours, adjust tension every 20 hours. Fluid Specifications Engine Oil Specification:...