Motorcycle Segment:
Motocross / Competition Off-Road
Target Audience:
Enthusiast riders, mechanics, and race teams for Yamaha YZ450F owners
Key Competitors Era:
Honda CRF450R, Kawasaki KX450F, Suzuki RM-Z450, KTM 450 SX-F
Yz450F Reputation:
Known for its powerful engine and agile handling, a dominant force in its class during its production years.
Manual Value Proposition:
Provides essential technical information for maintaining, troubleshooting, and repairing the specific model years, crucial for performance and longevity.
Systems Covered:
Engine, Chassis, Drivetrain, Suspension, Brakes, Electrical System, Fuel System, Cooling System, Lubrication System, Troubleshooting, Specifications, Maintenance, General Information
Estimated Page Count:
Refer to PDF content (typically 300-500 pages for comprehensive manuals of this era)
Manual Type:
Workshop Service Repair Manual
Engine Systems:
Engine disassembly, assembly, inspection, valve clearance adjustment, piston/cylinder inspection, crankshaft/connecting rod checks, timing chain replacement, oil pump service, cooling system maintenance, lubrication system diagnostics.
Chassis Systems:
Frame inspection, front fork disassembly/assembly/service, rear shock absorber service, steering system inspection and adjustment, swingarm and linkage maintenance, wheel bearing service, brake system bleeding and component replacement.
Drivetrain Systems:
Clutch assembly inspection and service, gearbox disassembly and assembly, chain and sprocket inspection and replacement.
Electrical Systems:
Wiring diagrams, ignition system troubleshooting, lighting system maintenance, battery service, CDI unit diagnostics, starter motor inspection.
Maintenance Procedures:
Regular servicing, oil and filter changes, air filter cleaning/replacement, spark plug replacement, chain lubrication and adjustment, brake pad inspection and replacement, coolant level checks.
Repair Procedures:
Full engine rebuild, transmission repair, suspension overhaul, brake caliper rebuilding, electrical component diagnosis and replacement, fuel system cleaning and repair.
Troubleshooting Guides:
Diagnostic trees for common starting problems, running issues, braking concerns, and electrical faults.
Diagnostic Capabilities:
Advanced diagnostics including ignition timing verification, fuel injection system checks (where applicable, though this model is carbureted), compression testing, and electrical circuit analysis.
Rebuild Instructions:
Detailed step-by-step instructions for complete engine disassembly and reassembly, including torque specifications for all critical fasteners and clearances for internal components.
Specification Accuracy:
Precise specifications for all mechanical and electrical components, including valve clearances, piston ring gap, bearing clearances, and torque values.
Engine Type:
Liquid-cooled, Four-stroke, DOHC, Single Cylinder
Engine Displacement:
449.7 cc
Bore X Stroke:
95.0 mm x 63.1 mm (typical for this generation)
Compression Ratio:
12.3:1 (typical for this generation)
Valve Train:
DOHC, 4 valves
Horsepower Estimate:
Approx. 53-56 HP (at crankshaft, depending on specific year and tuning)
Torque Estimate:
Approx. 34-36 lb-ft (at crankshaft, depending on specific year)
Fuel Delivery:
Keihin FCR-MX39 Carburetor (This generation utilizes a carburetor, not fuel injection).
Fuel Type:
Unleaded Gasoline, Octane Rating 91 or higher recommended.
Oil Type Recommendation:
Yamalube 4 (or equivalent SAE 10W-40, API SG, JASO MA) Motorcycle Oil
Oil Capacity With Filter:
1.05 L (1.11 US qt)
Oil Capacity Without Filter:
0.95 L (1.00 US qt)
Transmission Type:
Constant-mesh 5-speed
Clutch Type:
Wet, multiple-disc, cable-actuated
Gear Ratios:
Refer to manual for specific ratios (e.g., 1st: 2.462, 2nd: 1.789, 3rd: 1.409, 4th: 1.150, 5th: 0.917)
Overall Length:
Approx. 2,170 mm (85.4 in)
Overall Width:
Approx. 825 mm (32.5 in)
Overall Height:
Approx. 1,280 mm (50.4 in)
Seat Height:
Approx. 995 mm (39.2 in)
Wheelbase:
Approx. 1,485 mm (58.5 in)
Wet Weight:
Approx. 112 kg (247 lbs) (with all standard operating fluids and a full tank of fuel)
Dry Weight:
Approx. 103 kg (227 lbs)
Safety Ratings Motorcycle:
N/A (Motorcycles are not subject to the same crash ratings as automobiles)
Braking System:
Hydraulic disc brakes (front and rear)
Front Brake Spec:
270mm Hydraulic Disc
Rear Brake Spec:
245mm Hydraulic Disc
Frame Construction:
Aluminum Bilateral Beam Frame
Suspension Type:
Fully Adjustable KYB® Speed Sensitive System (SSS) front forks and KYB® piggyback rear shock absorber
Engine Oil Change:
Every 10-15 hours of riding or annually, whichever comes first (competition use).
Oil Filter Replacement:
Every 10-15 hours of riding or annually, concurrent with oil change.
Air Filter Cleaning:
After every few rides or as needed, depending on riding conditions (dusty conditions require more frequent cleaning).
Spark Plug Replacement:
Every 20-30 hours of riding or annually.
Valve Clearance Check:
Every 20-30 hours of riding or annually.
Coolant Type:
Yamaha All-Purpose Sealant Coolant (or equivalent ethylene glycol-based coolant with corrosion inhibitors, mixed 50/50 with distilled water).
Brake Fluid Type:
DOT 4 Hydraulic Brake Fluid
Fork Oil Type And Level:
Refer to manual for specific fork oil viscosity (e.g., Yamalube Fork Oil 01 or equivalent SAE 5W) and oil level (typically measured from the top of the inner tube with the spring removed).
Common Wear Items:
Clutch plates, brake pads, wheel bearings, steering bearings, swingarm/linkage bearings, valve seats and guides.
Reverse Cylinder Specifics 2010+:
Early models with the reverse cylinder had some minor refinements in later years, but the core design is robust. Proper maintenance of the intake tract is crucial to prevent debris ingress.
Overheating Potential:
As with any high-performance liquid-cooled engine, proper coolant levels and radiator maintenance are essential to prevent overheating, especially under strenuous use.
Yamaha Motorcycle Legacy:
Yamaha has a long and successful history in motorcycle racing, particularly in motocross, with the YZ lineage being a cornerstone of their off-road performance.
Yz450F Generations:
The 2009-2014 models represent the third generation of the YZ450F, characterized by significant chassis and engine updates compared to earlier models. Notably, Yamaha introduced a unique reverse-cylinder engine concept in the 2010 model year, which continued through 2014.
2009 Model Characteristics:
Still utilized a conventional engine orientation, known for its strong power delivery.
2010 Model Innovation:
Introduction of the revolutionary reverse-cylinder engine with the forward-facing intake and rearward-facing exhaust, aiming to improve mass centralization and handling.
Manufacturing Location:
Japan (primarily)
Motocross Magazine Awards:
The YZ450F series consistently received praise and awards from major motocross publications throughout these model years for its performance and handling.
Rider Reviews General:
Highly regarded by professional and amateur racers for its potent engine, capable suspension, and well-balanced chassis.
