Production Years Covered:
2000, 2001, 2002
Generation Identifier:
1st Generation (WR400F inception, transition to WR426F)
Engine Type Codes:
4-stroke, liquid-cooled, DOHC, 4-valve (per model variation)
Vehicle Segment:
Competition Enduro Motorcycle
Target Audience:
Off-road enthusiasts, motocross riders, enduro competitors
Key Competitors:
KTM EXC series, Honda CRF-X, Suzuki RM-Z, Kawasaki KX series (off-road variants)
Engine Configuration:
Powerful 4-stroke engine optimized for torque and tractable power delivery in off-road conditions.
Suspension:
High-performance, adjustable suspension systems (e.g., KYB or similar quality) designed for absorbing impacts and maintaining control on varied terrain.
Durability And Reliability:
Yamaha's reputation for building robust and reliable off-road machinery.
Manual Benefit:
Empowers owners to perform a wide range of maintenance and repair tasks, saving time and money while ensuring optimal performance and longevity.
Manual Coverage:
All systems, maintenance, and repairs
Estimated Page Count:
Hundreds (specific count not provided, but indicative of comprehensive coverage)
Manual Type:
Service Repair Manual
Supported Languages:
English (ENG), French (FRA), German (GER), Spanish (ESP)
Delivery Method:
ZIP Archive
Engine System:
Complete engine overhaul, internal components, cooling system, lubrication system, fuel system (carburetion), ignition system
Transmission System:
Gearbox inspection, maintenance, and repair; clutch operation and service
Chassis System:
Frame, suspension (front forks, rear shock), steering, wheels, hubs, spokes, braking system (front and rear)
Electrical System:
Wiring diagrams, lighting, ignition system components, battery, charging system, sensors
Bodywork And Plastics:
Removal and installation of body panels, seat, fuel tank, fenders
Routine Maintenance:
Oil changes, filter replacements, chain adjustment and lubrication, spark plug service, air filter cleaning/replacement
Troubleshooting:
Diagnostic procedures for common and uncommon issues, symptom analysis
Disassembly And Reassembly:
Complete step-by-step guides for all major components and systems
Performance Tuning:
Carburetor adjustments, basic engine tuning principles (within factory specifications)
Diagnostic Capabilities:
Advanced diagnostics with detailed explanations of component functions and failure modes
Rebuild Procedures:
Comprehensive instructions for full engine and gearbox rebuilds
Illustrations And Diagrams:
Hundreds of high-quality illustrations and detailed wiring diagrams
Print Readability:
High Quality, Fully Printable
Digital Binding:
Bookmarked (for easy navigation within PDF)
Digital Paper Simulation:
Simulated A4/Letter page layout for printing
Engine Type:
4-stroke, liquid-cooled, DOHC, 4-valve
Displacement Wr400F:
396 cc (approximate)
Displacement Wr426F:
426 cc (approximate)
Bore X Stroke Wr400F:
Not explicitly stated, but typical for this era: ~84 mm x 70 mm
Bore X Stroke Wr426F:
Not explicitly stated, but typical for this era: ~95 mm x 60 mm
Compression Ratio:
Typically around 12.0:1 to 13.0:1 (varies by year/model)
Horsepower Wr400F:
Approx. 45-50 HP (crankshaft)
Horsepower Wr426F:
Approx. 48-53 HP (crankshaft)
Torque:
Emphasis on strong mid-range and low-end torque for off-road traction.
Fuel Delivery:
Carbureted (e.g., Keihin FCR series carburetors)
Carburetor Size:
Typically 37-39mm (specific to model/year)
Fuel Type:
Unleaded gasoline, minimum octane rating typically 91 RON
Ignition Type:
CDI (Capacitor Discharge Ignition)
Overall Length:
Varies slightly by year, approximately 2170-2185 mm
Overall Width:
Varies slightly by year, approximately 815-830 mm
Overall Height:
Varies slightly by year, approximately 1275-1285 mm
Seat Height:
Approximately 985-990 mm
Ground Clearance:
Approximately 340-350 mm
Dry Weight:
Approximately 111-112 kg (varies by year/model)
Wet Weight:
Not explicitly stated, but significantly more than dry weight due to fluids.
Fuel Tank Capacity:
Approximately 9.0 - 10.0 Liters (including reserve)
Safety Standards:
Designed for off-road competition use; does not typically meet road-legal safety standards or ratings.
Braking System:
Hydraulic disc brakes (front and rear) for superior stopping power.
Suspension Handling:
Advanced suspension geometry and components for stability and control.
Frame Construction:
Strong, lightweight frame designed to withstand rigorous off-road use.
Ergonomics:
Designed for rider control and maneuverability in dynamic off-road environments.
Infotainment System:
N/A (Competition Enduro Motorcycle - no infotainment systems).
Driver Assistance Features:
N/A (Focus is on rider control and mechanical systems).
Connectivity Features:
N/A
Lighting System:
Basic headlight and taillight for visibility and potential limited street legality depending on local regulations, powered by the AC generator.
Engine Oil Change:
Typically every 10-20 hours of riding, or as specified in the manual.
Oil Filter Replacement:
Concurrent with oil changes, or as specified.
Air Filter Cleaning:
Frequent cleaning recommended, especially in dusty conditions (e.g., every few rides).
Spark Plug Inspection:
Typically every 20-30 hours of riding.
Valve Clearance Check:
Crucial for 4-stroke engines; typically every 20-40 hours, or as indicated in manual.
Chain Lubrication And Adjustment:
Frequent, as needed based on riding conditions.
Engine Oil Type:
Yamalube 4 (4-stroke motorcycle oil) SAE 10W-40, API SG or higher.
Engine Oil Capacity:
Approximately 1.0 - 1.2 Liters (dry fill), refer to manual for exact capacity and fill procedure.
Coolant Type:
High-quality permanent type antifreeze coolant (ethylene glycol based), mixed with distilled water at a 50:50 ratio.
Brake Fluid Type:
DOT 4 hydraulic brake fluid.
Cam Chain Tensioner:
Potential for wear or failure of the automatic cam chain tensioner leading to noise or engine damage; manual will detail inspection and replacement.
Carburetor Jetting:
May require re-jetting based on altitude, temperature, or modifications for optimal performance.
Suspension Seals:
Fork seal leaks can occur with hard use; manual covers seal replacement procedures.
Decompressor Mechanism:
Early models sometimes had issues with manual/automatic decompression systems; manual covers checks.
Yamaha Offroad Legacy:
Yamaha has a long-standing and highly successful history in off-road motorcycle racing and development, dating back decades with iconic models like the DT and YZ series.
Wr400F Introduction:
The WR400F was a significant evolution from Yamaha's YZ400F motocross bike, adapted for enduro riding with features like a wider gear ratio, lights, and a larger fuel tank.
Transition To Wr426F:
The WR426F, introduced later in this period, represented an increase in displacement, offering more power and torque, building upon the WR400F's foundation.
Manufacturing Location:
Primarily Japan
Sales Figures:
Popular in the burgeoning 4-stroke enduro market of the early 2000s.
Motocross Enduro Performance:
Yamaha's WR series has consistently been recognized for its competitive performance in enduro and off-road events throughout its production runs.
Reliability Reputation:
Yamaha's 4-stroke off-road bikes of this era generally received positive ratings for their robustness and reliability when properly maintained.
Emissions Standards:
Primarily designed for off-road use, emissions compliance would be specific to the market it was sold in and not a primary focus for this type of vehicle.
