Vehicle Type:
All-Terrain Vehicle (ATV)
Model Years Covered:
2004, 2005
Product Name:
Yamaha YFZ 450 2004-2005 ATV Service Factory Repair Manual PDF Download
Chassis Code General:
Often identified by VIN starting with JY4
Engine Code General:
4-stroke, 5-valve, DOHC, Liquid-cooled, Single-cylinder
Segment:
High-performance sport ATV
Target Audience:
Recreational riders, racers, off-road enthusiasts
Key Competitors:
Honda TRX450R, Suzuki LT-R450, Kawasaki KFX450R
Vehicle Highlight:
Renowned for its powerful engine and agile handling, establishing Yamaha as a leader in the sport ATV market.
Manual Highlight:
Provides essential information for maintaining peak performance and undertaking complex repairs on this iconic ATV.
Scope:
Comprehensive service and repair
Specific Sections:
Engine, transmission, chassis, suspension, brakes, electrical system, body, troubleshooting
Estimated Pages:
300-500 pages (typical for this era of service manual)
Type:
Factory Service Manual / Repair Manual
Powertrain:
Engine disassembly, assembly, tuning, cooling system, lubrication system, fuel system, exhaust system
Drivetrain:
Transmission operation, clutch service, final drive, chain adjustment
Chassis And Suspension:
Frame inspection, front suspension (A-arms, steering components), rear suspension (swingarm, shock absorber), wheel bearings, steering system
Brakes:
Hydraulic brake system (front and rear), caliper service, master cylinder service, brake fluid specifications, bleeding procedures
Electrical System:
Ignition system, lighting, starting system, charging system, battery maintenance, wiring diagrams, diagnostic procedures
Body And Trim:
Plastic body panel removal/installation, seat, fenders, handle bar assembly
Maintenance:
Oil changes, filter replacement, air filter cleaning/replacement, spark plug replacement, chain lubrication, brake adjustments
Troubleshooting:
Step-by-step diagnostic flowcharts for common issues (e.g., starting problems, poor performance, electrical faults)
Repair:
Detailed procedures for component disassembly, inspection, repair, and reassembly
Rebuilding:
Engine rebuild procedures, carburetor overhaul
Technical Data:
Torque specifications for all fasteners, valve clearances, timing procedures
Depth:
Factory-level detail, suitable for professional technicians and experienced DIY enthusiasts
Diagnostics:
Includes methods for diagnosing electrical and mechanical issues, often referencing specific tool usage
Engine Type:
4-stroke, DOHC, 5-valve cylinder head
Bore X Stroke:
95.0 mm x 63.1 mm
Compression Ratio:
11.9:1
Cooling System:
Liquid-cooled
Horsepower Approx:
Approximately 40-45 hp (claimed)
Torque Approx:
Approximately 40 Nm (claimed)
Fuel Delivery:
Mikuni BSR37 carburetor (or similar high-performance carb)
Fuel Type:
Unleaded gasoline, minimum 87 octane (AKI)
Oil Type:
Yamalube 4-stroke motorcycle oil or equivalent API SG or higher, JASO MA certified, SAE 10W-40 or 20W-50 depending on temperature
Oil Capacity W Filter:
Approx. 2.1 L (2.2 US qt)
Ignition System:
TCI (Transistor Controlled Ignition)
Spark Plug Type:
NGK CR9EIX or equivalent (Iridium recommended)
Transmission Type:
Constant mesh, 5-speed manual with reverse
Clutch Type:
Wet, multiple-disc
Final Drive:
O-ring sealed chain drive
Gear Ratios:
Detailed in manual (typically includes 1st through 5th gear ratios and reverse)
Transmission Oil Type:
Yamalube 4-stroke motorcycle oil or equivalent API SG or higher, JASO MA certified, SAE 10W-40 or 20W-50 (same as engine oil)
Transmission Oil Capacity:
Approx. 0.8 L (0.85 US qt)
Length:
Approx. 1830 mm (72.0 in)
Width:
Approx. 1215 mm (47.8 in)
Height:
Approx. 1040 mm (40.9 in)
Wheelbase:
Approx. 1280 mm (50.4 in)
Ground Clearance:
Approx. 250 mm (9.8 in)
Curb Weight:
Approx. 177 kg (390 lbs)
Fuel Tank Capacity:
Approx. 10 L (2.6 US gal)
Unit Of Measure:
Metric and Imperial (provided in manual)
Safety Standards:
Meets all applicable US EPA emission standards. Designed for off-road use only.
Braking System:
Dual hydraulic disc brakes (front), Single hydraulic disc brake (rear)
Suspension Type:
Independent front suspension, Swingarm rear suspension with Monoshock
Lighting:
Halogen headlights, taillight/brake light
Throttle Limiter:
Adjustable throttle stop screw (for rider control/training)
Infotainment System:
N/A (Sport ATV - focus is on performance, not comfort/entertainment features).
Driver Assistance Features:
N/A (Sport ATV - focus is on rider control and direct interaction).
Connectivity Features:
N/A (Sport ATV).
Engine Control:
Basic electronic ignition control (TCI), carburetor for fuel delivery. No complex ECU or electronic fuel injection.
Engine Oil Change:
Every 20 hours of operation or annually, whichever comes first.
Air Filter Cleaning:
Every 10 hours of operation or more frequently in dusty conditions.
Spark Plug Inspection:
Every 20 hours of operation.
Chain Lubrication Adjustment:
Every 10 hours of operation or more frequently as needed.
Valve Clearance Check:
Every 40 hours of operation or annually.
Coolant Type:
High-quality ethylene glycol-based antifreeze coolant (50/50 mix with distilled water)
Brake Fluid Type:
DOT 3 or DOT 4 brake fluid
Common Wear Items:
Clutch plates, chain and sprockets, brake pads, wheel bearings, tie rod ends.
Performance Related:
Carburetor jetting adjustments may be required for altitude or temperature changes. Overheating can occur under extreme load or poor airflow if cooling system is not maintained.
Maintenance Schedule Detail
Schedule Access:
The manual provides a detailed schedule of all required maintenance tasks and their intervals.
Manufacturer History:
Yamaha Motor Corporation, established in 1955, has a long-standing reputation for innovation and performance in motorcycles and powersports vehicles.
Yfz 450 Introduction:
The YFZ 450 was introduced in 2004 as Yamaha's flagship sport ATV, boasting a potent 450cc engine derived from their YZ motocross bikes, setting a new standard for performance.
Key Design Elements:
Lightweight chassis, powerful 5-valve engine, advanced suspension, and aggressive styling.
Manufacturing Location:
Primarily manufactured in Japan and/or USA for the North American market.
