🏷️ Basic Information

Make:

Yamaha

Model:

YZ250

Year:

2006

Vehicle Type:

Motocross Motorcycle

Engine Type:

2-Stroke

Chassis Code:

4SF

Engine Code Prefix:

5XC

👋 Introduction

Segment:

Competitive Open-Class Motocross

Purpose:

High-performance off-road competition and recreational riding

Key Rivals:

KTM 250 SX, Honda CR250R, Suzuki RM250, Kawasaki KX250

Engine Type:

Potent 249cc liquid-cooled 2-stroke engine known for its strong mid-range and top-end power delivery.

Suspension:

Advanced Kayaba (KYB) Speed Sensitive System (SSS) front forks and KYB rear shock absorber offering excellent adjustability and performance.

Chassis:

Lightweight aluminum frame providing excellent rigidity and rider feedback.

Braking:

Powerful front and rear disc brakes for confident stopping power.

📋 Manual Details

Documentation Type:

Service Repair Workshop Manual

Target Audience:

Technicians and advanced DIY mechanics

Estimated Page Count:

400+

Manual Format:

Digital Download (PDF)

Language:

English

File Format:

PDF

📖 Manual Coverage

Engine Systems:

Top-end overhaul (piston, rings, cylinder, head), bottom-end assembly (crankshaft, connecting rod, bearings), lubrication, cooling (radiator, hoses), fuel system (carburetor, jets, linkages), ignition system (CDI, stator, coil), exhaust system (pipe, silencer).

Drivetrain Systems:

Clutch operation and adjustment, transmission gears and shifting mechanism, final drive (chain and sprockets).

Chassis Systems:

Front suspension (fork internals, damping adjustments, seals), rear suspension (shock absorber rebuild, linkage system, swingarm), steering system (headset bearings, steering stem), braking system (front and rear caliper overhaul, master cylinder, brake lines, pad replacement), wheels and tires (spoke tension, hub bearings, tire mounting).

Electrical Systems:

Wiring diagrams, lighting (if applicable), ignition switch, kill switch, basic troubleshooting of electrical components.

Routine Maintenance:

Pre-ride inspections, chain lubrication and adjustment, air filter cleaning/replacement, spark plug service, oil changes (gearbox oil), brake fluid checks.

Repair Procedures:

Complete engine teardown and rebuild, transmission overhaul, suspension fork servicing, carburetor cleaning and tuning, brake system bleeding and component replacement.

Troubleshooting:

Diagnostic charts for common running issues (e.g., poor starting, misfiring, low power), wear diagnosis for engine components.

Assembly Instructions:

Detailed step-by-step assembly sequences with torque specifications for critical fasteners.

Diagnostic Capabilities:

Advanced, covering internal component wear, tolerances, and specialized measurement techniques.

Rebuild Scope:

Complete motorcycle rebuild, from engine internals to chassis components.

Special Tools:

Identification and usage of Yamaha-specific special tools required for certain procedures (e.g., flywheel puller, clutch holder).

📊 Manual Specifications

Document Quality:

High-resolution, clear digital images and text

Searchability:

Searchable text content for quick information retrieval

Printability:

Printable pages for convenient workshop use

Digital Binding:

N/A (Digital Format)

Digital Paper Equivalent:

Optimized for screen viewing and printing

⚙️ Engine Specifications

Engine Displacement:

249 cc

Bore X Stroke:

66.4 mm x 72.0 mm

Engine Layout:

Single-cylinder, 2-stroke, reed valve induction

Cooling System:

Liquid-cooled

Compression Ratio:

8.2:1 (low compression for pump gas)

Estimated Horsepower:

Approx. 45-50 HP (stock)

Estimated Torque:

Approx. 30-33 lb-ft (stock)

Carburetor Model:

Keihin PWK38S (38mm) with power jet

Fuel Type:

Unleaded gasoline (91 octane or higher recommended)

Fuel Mixture:

Pre-mix (50:1 ratio with high-quality 2-stroke oil like Yamalube 2R or equivalent)

Ignition Type:

Digital CDI (Capacitor Discharge Ignition)

Spark Plug:

NGK BR7ES or equivalent

Transmission Oil:

Yamalube SAE 10W-30 API SE Type CC or CD

Transmission Oil Capacity:

0.63 L (0.67 US qt, 0.55 UK qt)

🔧 Transmission

Transmission Type:

Constant-mesh 5-speed sequential

Gear Ratios:

1st: 2.615 (34/13), 2nd: 1.933 (29/15), 3rd: 1.500 (30/20), 4th: 1.235 (21/17), 5th: 1.050 (21/20)

Clutch Type:

Wet, multi-plate

Final Drive:

Chain drive, 520 O-ring type

📐 Dimensions

Overall Length:

2,170 mm (85.4 in)

Overall Width:

825 mm (32.5 in)

Overall Height:

1,280 mm (50.4 in)

Seat Height:

970 mm (38.2 in)

Wheelbase:

1,475 mm (58.1 in)

Ground Clearance:

355 mm (14.0 in)

Dry Weight:

96 kg (211.6 lbs)

Fuel Tank Capacity:

8.0 L (2.1 US gal, 1.8 UK gal)

🛡️ Safety Features

Safety Rating:

N/A (Off-road competition vehicle, not subject to road safety regulations)

Braking System:

Hydraulic disc brakes (front and rear) with large rotor diameters for enhanced stopping power.

Frame Construction:

Rigid aluminum frame designed for impact absorption and rider control.

Ergonomics:

Designed for rider control and balance in aggressive riding conditions.

💡 Technology Features

Infotainment System:

N/A (Pure performance off-road motorcycle)

Driver Assistance Features:

N/A (No electronic rider aids)

🔧 Maintenance

Engine Top End Rebuild:

Recommended every 40-60 hours of aggressive riding, or sooner based on performance degradation.

Piston Ring Replacement:

Recommended every 20-30 hours, or upon top-end inspection.

Spark Plug Replacement:

Check and clean every 5-10 hours, replace as needed.

Air Filter Cleaning:

Clean after every few rides, or more frequently in dusty conditions.

Chain Lubrication Adjustment:

Lubricate every ride, check and adjust tension every 5-10 hours.

Gearbox Oil Spec:

Yamalube SAE 10W-30 API SE Type CC or CD (or equivalent)

Brake Fluid Spec:

DOT 3 or DOT 4 brake fluid

Coolant Spec:

Permanent type antifreeze coolant (50% solution with distilled water)

Clutch Wear:

Common for high-performance 2-strokes to experience clutch plate wear due to aggressive use. Regular inspection and replacement are advised.

Carburetor Jetting:

Carburetor jetting may need adjustment based on altitude, temperature, and modifications to achieve optimal performance and prevent premature wear.

Suspension Seals:

Fork seal leaks can occur with hard impacts. Regular inspection and maintenance are crucial.

Power Jet Carb:

The power jet on the carburetor can be a point of sensitivity; proper cleaning and adjustment are key to consistent performance.

📚 Vehicle History

Heritage:

Yamaha has a long and successful history in motocross, with the YZ line being a dominant force for decades, known for its performance and reliability.

Yz250 Legacy:

The YZ250 has been a staple in Yamaha's lineup since its introduction in the 1970s, evolving through numerous chassis and engine updates. The 2006 model represents a refinement of the aluminum frame generation, building on previous generations with improved suspension and engine characteristics.

Production Era:

This generation with the aluminum frame (including the 2006 model) was produced from approximately 2002 to 2014.

Manufacturing Location:

Japan

🏆 Awards & Recognition

Motocross Awards:

The YZ250 platform has consistently received praise and awards from motorcycle publications for its class-leading performance and handling throughout its production years.

Performance Ratings:

Generally rated highly by critics for its potent engine, advanced suspension, and lightweight chassis, making it a formidable competitor in its class.

Emissions Certification:

N/A (Off-road vehicles typically have different or no emissions certifications compared to street-legal vehicles).