Segment:
High-performance 250cc four-stroke motocross competition bike
Key Competitors:
Honda CRF250R, Kawasaki KX250F, Suzuki RM-Z250
Engine Technology:
Compact, powerful four-stroke engine with DOHC and 5-valve configuration for improved breathing and performance.
Suspension:
Advanced Kayaba suspension components offering extensive adjustability for varied track conditions.
Handling:
Lightweight chassis and refined geometry contributing to agile handling and rider control.
Engine:
Full engine disassembly, assembly, specifications, and troubleshooting
Transmission:
Clutch, gearbox, shifting mechanisms, and related components
Fuel System:
Carburetor (Mikuni VM34SS), fuel pump, fuel lines, and tank
Suspension:
Front (Kayaba USD, adjustable) and Rear (Kayaba monoshock, adjustable) suspension systems
Brakes:
Front and rear hydraulic disc brakes, caliper maintenance, and fluid replacement
Electrical System:
Ignition system, lighting, wiring diagrams, battery, and charging system
Cooling System:
Radiators, water pump, coolant hoses, and thermostat
Exhaust System:
Exhaust pipe, silencer, and mounting hardware
Chassis And Frame:
Frame inspection, steering head, and rear swingarm
Wheels And Tires:
Rim maintenance, spoke tension, and tire installation
Scheduled Maintenance:
Oil changes, filter replacements, chain lubrication, valve clearance checks
Disassembly And Assembly:
Complete engine, transmission, suspension, and chassis component procedures
Troubleshooting:
Diagnostic procedures for common and uncommon issues
Specifications And Measurements:
Torque specifications, clearances, and critical measurements
Wiring Diagrams:
Detailed electrical system schematics
Rebuild Guides:
Comprehensive step-by-step rebuild instructions for major components
Depth:
Comprehensive: Covers all aspects from routine maintenance to complete engine and chassis rebuilds.
Visual Aids:
Includes pictures and part diagrams for clarity
Engine Type:
249cc, Liquid-cooled, 4-stroke, Single-cylinder, DOHC, 5-valve
Bore X Stroke:
76.0 mm x 55.0 mm
Compression Ratio:
12.5:1
Horsepower:
Approx. 38-40 HP (estimated, actual may vary)
Torque:
Approx. 20-22 lb-ft (estimated, actual may vary)
Carburetor:
Mikuni VM34SS
Fuel Type:
Unleaded gasoline, minimum 91 octane
Oil Type:
Yamalube 4 (or equivalent API SG, SAE 10W-40)
Oil Capacity:
1.10 L (1.16 US qt)
Transmission Type:
Constant-mesh 5-speed
Clutch Type:
Wet, multi-plate
Gear Ratios:
1st: 2.615 (34/13), 2nd: 1.875 (30/16), 3rd: 1.500 (27/18), 4th: 1.235 (21/17), 5th: 1.000 (21/21)
Transmission Oil:
Yamalube 4 (or equivalent API SG, SAE 10W-40) - shared with engine oil
Safety Standards:
N/A (Competition Off-Road Motorcycle - not road legal or safety rated by governing bodies for street use)
Braking System:
Hydraulic disc brakes front and rear for strong stopping power.
Handling Characteristics:
Designed for stability and control during high-speed maneuvers and jumps.
Frame Construction:
Lightweight yet strong aluminum frame for rider confidence.
Infotainment System:
N/A (Pure competition motocross bike)
Driver Assistance Features:
N/A (Pure competition motocross bike)
Connectivity Features:
N/A (Pure competition motocross bike)
Ignition System:
CDI (Capacitor Discharge Ignition)
Cooling System Type:
Forced air and liquid cooling
Engine Oil Change:
Every 10-15 hours of riding or as per manual recommendations.
Air Filter Cleaning:
After every ride, especially in dusty conditions.
Spark Plug Check:
Every 20-30 hours of riding.
Valve Clearance Check:
Every 20-30 hours of riding.
Chain Lubrication And Adjustment:
Before every ride or as needed.
Brake Fluid Change:
Annually or as recommended.
Engine Oil:
Yamalube 4 (or equivalent API SG, SAE 10W-40)
Coolant:
High-quality ethylene glycol-based coolant with distilled water (50/50 mix)
Brake Fluid:
DOT 3 or DOT 4 brake fluid
Carburetor Tuning:
Can be sensitive to altitude and temperature changes, requiring occasional re-jetting.
Clutch Wear:
Clutch plates can wear over time, particularly with aggressive riding. Regular inspection and replacement are advised.
Suspension Seals:
Fork and shock seals can degrade with use and impact, requiring periodic inspection and potential replacement.
Heritage:
Yamaha has a long and distinguished history in motocross and off-road racing, consistently developing innovative and competitive machines.
Yzf Lineage:
The YZ250F line, introduced in 2001, marked Yamaha's successful entry into the 250cc four-stroke motocross category, quickly gaining popularity for its power and handling.
2005 Updates:
The 2005 model featured chassis refinements, improved suspension settings, and engine tweaks for enhanced performance and rideability over previous years.
Manufacturing Location:
Japan
