Production Years Covered:
2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
Chassis Code Range:
Specific chassis codes vary by model year and regional designation. Consult the manual for precise identification.
Category:
Off-Road Motorcycle / Enduro
Rivals:
Competed against models from KTM (e.g., EXC series), Honda (CRF series), Suzuki (DR-Z series), and Kawasaki (KLX series) during its production run.
Vehicle Focus:
Performance-oriented off-road motorcycle designed for competition and demanding terrain. Known for its potent engine and robust chassis.
Performance Focus:
The WR426F was lauded for its powerful engine and capable suspension, making it a strong contender for both racing and aggressive trail riding.
Coverage:
Comprehensive coverage for all aspects of Yamaha WR426F maintenance and repair across model years 2000-2008.
Estimated Page Count:
Hundreds of pages (exact count not provided, typical for workshop manuals of this scope).
Type:
Workshop Service Manual / Repair Manual
Delivery Method:
Instant Download
Accessibility:
Digital PDF, allowing for easy search, zoom, and selective printing of relevant sections.
Covered Systems:
Engine, Fuel System, Ignition System, Lubrication System, Cooling System, Transmission, Clutch, Chassis, Suspension (Front and Rear), Braking System (Front and Rear), Electrical System, Wiring Diagrams, Bodywork, Special Tools, Troubleshooting.
Wiring Diagrams Coverage:
Detailed wiring diagrams are included, essential for diagnosing and repairing electrical faults.
Chassis And Frame:
Covers inspection, maintenance, and repair of the frame, subframe, and all chassis components.
Included Procedures:
Periodic Maintenance Charts, Step-by-Step Repair Instructions, Overhaul Procedures, Troubleshooting Guides, Diagnostic Procedures, Component Removal and Installation, Torque Specifications, Fluid Capacities, Electrical System Diagnostics, Wiring Harness Repair.
Engine Rebuild Procedures:
Comprehensive instructions for engine disassembly, inspection, repair, and reassembly, including critical torque values and tolerances.
Suspension Overhaul:
Detailed guides for servicing and rebuilding front forks and rear shock absorbers, including oil levels and pressures.
Troubleshooting Guides:
Detailed guides for diagnosing common and uncommon problems across all vehicle systems.
Depth:
Professional-level detail suitable for factory technicians, with sufficient clarity for experienced DIY mechanics. Covers routine maintenance to complete engine and chassis overhauls.
Diagnostic Capabilities:
Includes troubleshooting charts and symptom-based diagnostics to help identify the root cause of problems.
Torque Specifications:
Includes precise torque specifications for all critical fasteners, crucial for safe and correct assembly.
Engine Type:
4-Stroke, Liquid-Cooled, DOHC, Single Cylinder
Bore X Stroke:
Approx. 95.0 mm x 60.1 mm (specifics may vary slightly by year).
Compression Ratio:
Approx. 12.5:1 (specifics may vary slightly by year).
Horsepower:
Estimated 50-55 HP at the crank (exact figures not officially published, but representative for the class).
Torque:
Estimated 40-45 lb-ft (exact figures not officially published, but representative for the class).
Fuel Delivery:
Carburetor (likely Mikuni, specific model varies by year, e.g., VM34/1)
Ignition System:
CDI (Capacitor Discharge Ignition)
Lubrication Type:
Wet Sump (integrated with transmission oil)
Dry Weight:
Approx. 112 kg (247 lbs) - this can vary slightly by year and equipment.
Overall Length:
Approx. 2,180 mm (85.8 in) - typical for the model range.
Overall Width:
Approx. 815 mm (32.1 in) - typical for the model range.
Overall Height:
Approx. 1,235 mm (48.6 in) - typical for the model range.
Wheelbase:
Approx. 1,475 mm (58.1 in) - typical for the model range.
Ground Clearance:
Approx. 335 mm (13.2 in) - typical for the model range.
Seat Height:
Approx. 960 mm (37.8 in) - typical for the model range.
Front Tire Size:
80/100-21 (typical for enduro, check manual for exact spec).
Rear Tire Size:
110/100-18 (typical for enduro, check manual for exact spec).
Oil Change Interval:
Typically every 10-15 hours of riding or as specified in the manual. Exact interval depends on riding conditions.
Air Filter Cleaning:
Frequent cleaning recommended, especially in dusty conditions. Check every few rides.
Spark Plug Replacement:
Refer to manual; generally inspected at oil changes and replaced based on condition or mileage/hours.
Engine Oil Type:
Yamalube (or equivalent) 4-stroke motorcycle oil, SAE 10W-40 or 10W-50. Check manual for precise viscosity based on temperature range.
Engine Oil Capacity:
Approx. 1.0-1.1 Liter (check manual for exact capacity with filter change).
Coolant Type:
High-quality, permanent type coolant (ethylene glycol base) mixed with distilled water (50/50 ratio). Yamaha Coolant recommended.
Brake Fluid Type:
DOT 3 or DOT 4 Brake Fluid (check manual for specific recommendation).
Transmission Oil Type:
Yamalube (or equivalent) 4-stroke motorcycle oil, SAE 10W-40 or 10W-50. Same as engine oil for this model.
Transmission Oil Capacity:
Approx. 0.7-0.8 Liters (check manual for exact capacity).
Common Wear Items:
Clutch plates, piston rings, valve stem seals, wheel bearings, steering head bearings, swingarm pivot bearings due to off-road usage.
Carburetor Tuning:
Can require meticulous tuning for optimal performance across different altitudes and temperatures.
Suspension Maintenance:
Regular fork seal and shock maintenance is crucial for consistent performance.
Engine Idle Instability:
Can sometimes exhibit unstable idle if carburetor or air leaks are present. Addressed in troubleshooting section.
Yamaha Off Road Legacy:
Yamaha has a long and distinguished history in off-road motorcycle racing and production, dating back to the early days of motocross and enduro. The WR series is a direct descendant of this racing pedigree.
Wr426F Development:
The WR426F replaced the WR400F, bringing increased displacement and performance. It was part of Yamaha's continuous development of their off-road lineup, aiming to provide competitive machines for enduro and trail riding. It was later succeeded by the WR450F.
Engine Update Context:
The transition from 400cc to 426cc in Yamaha's WR line was driven by the need to increase low-end torque and overall power to remain competitive in the evolving enduro racing landscape.
Manufacturing Origin:
Japan (primarily)
