🏷️ Basic Information

Make:

Yamaha

Model:

YZ250

Model Variant:

Two-Stroke Motocross

Product Type:

Service Repair Manual

Applicable Years:

1997, 1998, 1999, 2001, 2002

👋 Introduction

Segment:

High-Performance Motocross Competition

Target Audience:

Motocross Racers, Enthusiasts, Mechanics

Key Competitors:

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

Vehicle Reputation:

Known for its potent two-stroke power and agile handling

Manual Value:

Essential for maintaining peak performance and longevity of the YZ250

📋 Manual Details

Engine Overhaul:

Complete

Transmission Repair:

Complete

Suspension Service:

Front and Rear Fork, Shock Absorber

Brake System Maintenance:

Front and Rear Disc Brakes

Electrical System Diagnostics:

Ignition, Lighting, Charging

Chassis And Frame Service:

Complete

Cooling System:

Liquid Cooling System

Fuel System Maintenance:

Carburetor, Fuel Tank, Lines

Exhaust System Service:

Pipe and Silencer

Troubleshooting Guide:

Comprehensive Diagnostics

Scheduled Maintenance:

Intervals and Procedures

Estimated Pages:

300-400

Type:

Factory Service Manual

Language:

English

Format:

Digital Download (PDF)

📖 Manual Coverage

Engine Mechanical:

Cylinder, Piston, Crankshaft, Connecting Rod, Crankcase

Engine Tuning:

Carburetor Jetting, Ignition Timing

Clutch System:

Assembly, Adjustment, Components

Gearbox Internals:

Gears, Shift Drum, Forks, Bearings

Front Suspension Forks:

Disassembly, Reassembly, Oil Change, Seal Replacement

Rear Suspension Shock:

Rebuild, Damping Adjustments, Linkage Service

Front Brake Assembly:

Caliper, Master Cylinder, Rotor, Hoses

Rear Brake Assembly:

Caliper, Master Cylinder, Rotor, Hoses

Wheels And Tires:

Spoke Tensioning, Bearing Replacement, Tire Mounting

Ignition System:

CDI Unit, Spark Plug, Coil, Flywheel

Cooling System Components:

Radiator, Hoses, Water Pump

Carburetor Components:

Mikuni VM Series, Jetting, Float Adjustment

Exhaust System Components:

Expansion Chamber, Silencer Packing

Frame And Bodywork:

Frame Inspection, Subframe, Plastics

Controls And Linkages:

Throttle, Clutch Lever, Shift Lever, Cables

Routine Maintenance:

Oil Changes, Filter Cleaning, Chain Adjustment

Engine Rebuild:

Top-End and Bottom-End Overhaul

Transmission Rebuild:

Gearbox Disassembly and Reassembly

Suspension Rebuild:

Fork Seal Replacement, Shock Service

Brake System Bleeding:

Hydraulic System Service

Carburetor Cleaning And Adjustment:

Jet Replacement, Float Level Setting

Electrical Troubleshooting:

Wiring Diagrams, Fault Finding

Clutch Adjustment:

Lever and Cable Settings

Wheel Truing And Spoke Tensioning:

Radial and Lateral Alignment

Bearing Replacement:

Wheel Hubs, Steering Stem, Swingarm

Spark Plug Replacement:

Gap and Torque Specifications

Coolant Flush And Replacement:

System Bleeding

Silencer Repacking:

Performance and Sound Management

Troubleshooting Common Issues:

Hesitation, Stalling, Overheating

Depth:

Comprehensive Rebuild and Diagnostic Procedures

Torque Specifications:

Detailed for all critical fasteners

Clearances:

Piston to Cylinder, Ring Gap

Wiring Diagrams:

High-quality, color-coded (if applicable to source)

Special Tools:

Identification and usage of specialized tools

📊 Manual Specifications

Format:

PDF

Searchable:

Yes

Printable:

Yes

Image Resolution:

High-resolution for clarity

Binding:

N/A (Digital Download)

Paper Quality:

N/A (Digital Download)

⚙️ Engine Specifications

Type:

Liquid-Cooled, 2-Stroke, Reed Valve

Displacement:

249 cc (15.2 cu in)

Bore X Stroke:

68.0 mm x 68.0 mm (2.68 in x 2.68 in)

Compression Ratio:

8.2:1 (Approximate, varies by specific year/tuning)

Carburetor:

Mikuni VM29SS (Typical)

Ignition:

CDI (Capacitor Discharge Ignition)

Horsepower Peak:

Approximately 45-50 HP (at crankshaft, varies by year and tuning)

Torque Peak:

Approximately 28-30 lb-ft (at crankshaft, varies by year and tuning)

Fuel Type:

Unleaded Gasoline (91-98 Octane Recommended)

Fuel Mixture:

2-Stroke Pre-mix (Refer to manual for exact ratio, typically 30:1 or 40:1)

🔧 Transmission

Type:

5-Speed Constant Mesh

Clutch:

Wet, Multi-plate

Optional Features:

N/A for standard motocross models

Gear Ratios:

Detailed in manual for specific years

Final Drive:

Chain Drive

📐 Dimensions

Length:

Approx. 2165 mm (85.2 in)

Width:

Approx. 815 mm (32.1 in)

Height:

Approx. 1285 mm (50.6 in)

Wheelbase:

Approx. 1475 mm (58.1 in)

Ground Clearance:

Approx. 345 mm (13.6 in)

Seat Height:

Approx. 990 mm (39.0 in)

Dry Weight:

Approx. 99 kg (218 lbs)

Fuel Capacity:

Approx. 8.0 Liters (2.1 US gal)

🛡️ Safety Features

Safety Ratings:

N/A (Off-road Competition Vehicle)

Braking System:

Hydraulic Disc Front and Rear

Frame Construction:

Rigid Steel Perimeter Frame

💡 Technology Features

Infotainment System:

N/A (Pure Motocross Competition Vehicle)

Driver Assistance Features:

N/A (Pure Motocross Competition Vehicle)

Connectivity Options:

N/A (Pure Motocross Competition Vehicle)

🔧 Maintenance

Oil Change Frequency:

Every 10-15 hours of riding (Refer to manual for precise intervals based on riding conditions)

Air Filter Cleaning:

After every few rides or as needed based on dust conditions

Spark Plug Inspection:

Every 10-20 hours of riding

Top End Rebuild:

As needed, typically every 50-100 hours of hard riding (Manual provides detailed guidance)

Engine Oil:

Yamalube 2-Stroke or equivalent API TC, JASO FD rated oil (for pre-mix)

Transmission Oil:

Yamalube Gear Oil (GL-4, SAE 80W) or equivalent

Fork Oil:

Refer to manual for specific grade and quantity (e.g., Showa SS-02 or equivalent)

Coolant:

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

Common Wear Items:

Clutch plates, Piston rings, Spark plugs, Fork seals, Wheel bearings

Potential Problems:

Carburetor jetting sensitivity to altitude/temperature, reed valve wear affecting powerband

Preventative Maintenance:

The manual details a comprehensive schedule for preventative maintenance to ensure reliability and performance.

📚 Vehicle History

Yamaha Motorsport Legacy:

Yamaha has a long and storied history in motocross, with the YZ line being a cornerstone since the 1970s.

Yz250 Development:

The YZ250 received significant updates throughout the 1990s, focusing on engine power, suspension performance, and chassis refinement. These model years represent a mature and highly competitive iteration of the bike.

Manufacturing Location:

Japan

🏆 Awards & Recognition

Industry Awards:

The Yamaha YZ250 line has consistently been recognized for its class-leading performance and racing success.

Magazine Reviews:

Highly rated by motocross publications of its era for its power and handling characteristics.