🏷️ Basic Information

Make:

Yamaha

Model:

YZ250

Model Variant:

YZ250X

Year:

2008

Engine Type:

2-Stroke

Product Identifier:

Now Yamaha YZ250 YZ 250 2008 08 2-Stroke Service Repair Workshop Manual

👋 Introduction

Motorcycle Segment:

High-performance motocross/off-road competition motorcycle.

Target Audience:

Motocross racers, off-road enthusiasts, and mechanics who maintain and repair the Yamaha YZ250.

Key Competitors:

KTM 250 SX, Honda CR250R, Kawasaki KX250, Suzuki RM250 (during the respective model years).

Engine Performance:

Renowned for its potent, high-revving 2-stroke powerband, agile handling, and competitive performance.

Chassis Design:

Lightweight aluminum frame, advanced suspension, and rider-centric ergonomics contribute to exceptional maneuverability.

📋 Manual Details

Manual Type:

Service Repair Workshop Manual

Language:

English

Format:

Digital (likely PDF)

Page Count:

Not specified in product description, but typically comprehensive for workshop manuals.

📖 Manual Coverage

Engine Mechanical:

Detailed diagnosis, disassembly, inspection, repair, and reassembly of the 2-stroke engine, including top-end (cylinder, piston, rings), bottom-end (crankshaft, connecting rod, bearings), cooling system (if applicable, though typically air-cooled), lubrication system (pre-mix or oil injection system if applicable).

Fuel System:

Carburetor tuning, cleaning, and overhaul (including jetting specifications), fuel pump and lines (if applicable), fuel tank inspection and cleaning.

Ignition System:

CDI unit testing, ignition coil inspection, spark plug specifications, timing adjustments (if applicable).

Transmission Drivetrain:

Clutch operation, inspection, and replacement; gearbox disassembly, inspection, and repair; shift mechanism; final drive (chain and sprockets) maintenance and adjustment.

Suspension Front:

Fork disassembly, seal replacement, oil level and type specifications, damping adjustment, general inspection and repair of the telescopic forks.

Suspension Rear:

Monoshock rear suspension system, including linkage lubrication, shock absorber inspection, servicing (if user-serviceable), and spring adjustment.

Brakes Front:

Hydraulic front brake system, including caliper disassembly, piston inspection, seal replacement, brake pad replacement, rotor inspection and measurements, brake fluid type and bleeding procedures.

Brakes Rear:

Hydraulic rear brake system, including caliper disassembly, piston inspection, seal replacement, brake pad replacement, rotor inspection and measurements, brake fluid type and bleeding procedures.

Wheels Tires:

Spoke tension inspection and adjustment, wheel bearing maintenance, tire pressure recommendations, tire replacement procedures.

Electrical System:

Wiring diagrams, lighting system (headlight, taillight), kill switch functionality, battery maintenance (if applicable for lighting/horn), basic troubleshooting of electrical components.

Cooling System:

Typically air-cooled for this model, so focus would be on fin cleaning and ensuring adequate airflow.

Frame Chassis:

Frame inspection for damage or cracks, steering head bearing maintenance, swingarm bearing inspection and lubrication, general chassis component checks.

Bodywork:

Removal and installation of plastic body panels, seat, fuel tank cover, fender inspection and repair/replacement.

Routine Maintenance:

Oil changes (gear oil), chain adjustment and lubrication, air filter cleaning, spark plug inspection, bolt torque checks, general cleaning and lubrication.

Troubleshooting:

Diagnostic procedures for common engine performance issues, electrical faults, and mechanical problems.

Engine Rebuild:

Complete engine overhaul procedures, including piston ring gap, cylinder honing, crankshaft runout, and bearing clearances.

Suspension Servicing:

Fork oil replacement, fork seal replacement, rear shock linkage service.

Brake Service:

Brake pad replacement, caliper servicing, brake bleeding.

Carburetor Overhaul:

Complete cleaning, jetting, and adjustment procedures for the carburetor.

Electrical Diagnosis:

Troubleshooting common electrical system faults using wiring diagrams.

Wheel Truing:

Spoke tension adjustment for wheel alignment and truing.

Diagnostic Capabilities:

Comprehensive diagnostic charts for identifying and resolving various operational issues.

Specification Data:

Detailed torque specifications, clearances, fluid capacities, and wear limits for all major components.

Repair Procedures:

Step-by-step instructions with diagrams for virtually all repair and maintenance tasks.

Rebuild Guidance:

In-depth guidance for complete engine and gearbox rebuilds.

📊 Manual Specifications

File Type:

Likely PDF (Portable Document Format)

Searchability:

Expected to be fully text-searchable for quick information retrieval.

Print Readability:

Designed for clarity, with sharp text and legible diagrams.

Diagrams Illustrations:

Includes detailed line drawings, exploded views, and photographic illustrations.

Binding Style:

Digital format implies no physical binding. If a printed version were available, it would likely be coil-bound or saddle-stitched for lay-flat usability.

Paper Quality:

N/A for digital format, but original manuals are typically printed on durable, coated paper suitable for workshop environments.

⚙️ Engine Specifications

Engine Displacement:

249cc

Engine Configuration:

Single-cylinder, 2-stroke, reed valve induction, liquid-cooled (though some older variants were air-cooled, the 2008 YZ250 is liquid-cooled).

Bore X Stroke:

66.4 mm x 72.0 mm

Compression Ratio:

8.7:1 (typical for YZ250 models of this era, check manual for exact figure)

Valve Mechanism:

Reed valve induction

Cooling Method:

Liquid-cooled

Horsepower:

Approximately 45-50 HP (actual figure varies based on tuning and conditions, manual will provide specific data).

Torque:

Not typically published in standardized torque figures for this type of motorcycle, but known for strong mid-range pull.

Carburetor Model:

Keihin PWK38 (typical for this model, verify in manual).

Fuel Type:

Unleaded gasoline, 91 octane or higher (premium).

Oil Mixture:

Yamaha recommends Yamalube 2R (or equivalent 2-stroke racing oil) mixed with gasoline at a 50:1 ratio.

🔧 Transmission

Transmission Type:

5-speed, constant mesh

Clutch Type:

Wet, multi-plate

Final Drive:

Chain drive

📐 Dimensions

Overall Length:

2160 mm (approx.)

Overall Width:

825 mm (approx.)

Overall Height:

1275 mm (approx.)

Seat Height:

990 mm (approx.)

Wheelbase:

1475 mm (approx.)

Dry Weight:

97 kg (approx., without fluids)

Wet Weight:

Not typically published, but significantly heavier than dry weight with all fluids.

Fuel Tank Capacity:

8.0 liters (approx.)

🛡️ Safety Features

Safety Certification:

Off-road competition vehicles are not typically subject to road-legal safety certifications or crash ratings.

Braking System:

Dual hydraulic disc brakes (front and rear) for effective stopping power.

Ergonomics:

Designed for rider control and maneuverability in off-road conditions.

💡 Technology Features

Infotainment Features:

As a pure motocross/off-road competition vehicle, it does not feature infotainment systems like stereos or navigation.

Driver Assistance Systems:

No electronic driver assistance systems are present, focusing on direct rider control.

Connectivity Options:

No wireless or digital connectivity features are included.

🔧 Maintenance

Engine Oil Change:

Every 10-15 hours of operation or as specified in the manual, particularly after hard use.

Air Filter Cleaning:

After every few rides or more frequently in dusty conditions.

Chain Lubrication Adjustment:

Before every ride or as needed based on riding conditions.

Spark Plug Inspection:

Regularly, typically every 5-10 hours of riding, and replace as needed.

Top End Rebuild:

Typically every 50-100 hours of racing or hard use, depending on rider and conditions.

Transmission Oil Type:

Yamalube Hypoid Gear Oil GL-4 (or equivalent SAE 80W/90 hypoid gear oil).

Coolant Type:

Yamahaitrile Coolant (or equivalent permanent type antifreeze/coolant with corrosion inhibitors) mixed with distilled water at a 50:50 ratio.

Brake Fluid Type:

DOT 3 or DOT 4 hydraulic brake fluid.

Clutch Wear:

Clutch plates can wear relatively quickly under aggressive riding conditions, requiring periodic replacement. The manual details inspection and replacement procedures.

Carburetor Jetting:

Proper carburetor jetting is crucial for optimal performance and longevity. Altitude and temperature changes require adjustments. The manual provides baseline jetting and troubleshooting.

Suspension Maintenance:

Regular fork oil changes and seal checks are important to maintain optimal suspension performance and prevent leaks.

Cooling System Management:

Ensuring radiators are clean and free of debris is vital for preventing overheating in this liquid-cooled machine.

📚 Vehicle History

Yamaha Offroad Legacy:

Yamaha has a long and successful history in off-road motorcycle racing, particularly with its YZ line, dating back to the 1970s. The YZ250 is a flagship model known for its durability and competitive spirit.

Yz250 Development:

The YZ250 has undergone continuous development, with major revisions in chassis and engine technology over the years. The 2008 model represents a mature iteration of the platform, building on years of racing feedback.

Production Years:

The YZ250 has been in continuous production since its introduction, with the 2008 model being part of its highly successful 3rd generation evolution.

🏆 Awards & Recognition

Motocross Awards:

The Yamaha YZ250 line has consistently received praise and awards within the motocross and off-road community for its performance, durability, and competitive edge. Specific awards for the 2008 model would be found in period reviews and race results.