Target User:
Owners and technicians of the Yamaha WR400F (1998-1999 models) seeking in-depth repair and maintenance guidance.
Value Proposition:
Offers comprehensive factory-level technical information, including parts diagrams, which is crucial for accurate repairs and maintenance, often exceeding the scope of generic online resources.
Manual Type:
Combines a full service repair manual with parts diagrams, providing a holistic resource for vehicle upkeep and restoration.
Language Options:
Multilingual support (ENG-FRA-GER) enhances usability for a wider international audience.
Engine:
Complete engine disassembly, assembly, tuning, and troubleshooting
Fuel System:
Carburetor (Mikuni TM40), fuel tank, fuel lines, and filters
Ignition System:
CDI ignition system, spark plug, coil, and wiring
Transmission:
5-speed gearbox, clutch assembly, internal components, and lubrication
Suspension:
Front forks (upside-down), rear monoshock suspension, adjustments, and rebuild procedures
Brakes:
Front and rear hydraulic disc brakes, master cylinders, calipers, and bleeding procedures
Electrical System:
Wiring diagrams, lighting, battery, starter, charging system (stator/rotor), and switches
Cooling System:
Liquid-cooled engine, radiator, hoses, thermostat, and coolant specifications
Exhaust System:
Exhaust pipe, silencer, and gasket replacement
Frame And Bodywork:
Frame inspection, plastic body panels, seat, and handlebars
Wheels And Tires:
Wheel assembly, spoke tensioning, and tire fitment
Maintenance:
Regular servicing, oil changes, filter replacements, chain adjustment, spark plug checks
Troubleshooting:
Diagnostic guides for common problems, electrical issues, and engine performance
Repair:
Step-by-step instructions for component disassembly, repair, and reassembly
Disassembly Reassembly:
Detailed procedures for complete vehicle and component teardown and rebuild
Depth Of Coverage:
Comprehensive, suitable for professional mechanics and experienced DIY enthusiasts
Illustrations:
Hundreds of high-quality illustrations and diagrams
Wiring Diagrams:
Full color wiring diagrams for the electrical system
Parts Diagrams:
Exploded view parts diagrams for component identification and ordering
Engine Type:
4-stroke, Liquid-cooled, DOHC, 5-valve, Single-cylinder
Bore X Stroke:
84.0 mm x 70.0 mm
Compression Ratio:
12.5:1
Horsepower Est:
Approx. 45-50 HP (figures may vary based on tuning and emissions regulations)
Torque Est:
Approx. 35-40 Nm (figures may vary)
Carburetor Model:
Mikuni TM40 Flat-slide Carburetor
Fuel Type:
Unleaded gasoline (91-98 RON recommended)
Fuel Tank Capacity:
7.0 Liters (1.85 US gal)
Type:
Constant-mesh, 5-speed
Clutch Type:
Wet, multi-plate
Gear Ratios:
Specific ratios detailed within the manual (e.g., 1st: 2.714, 2nd: 1.867, 3rd: 1.400, 4th: 1.130, 5th: 0.917)
Final Drive:
O-ring sealed chain
Transmission Oil Type:
Yamalube 4 (or equivalent SAE 10W-30 API SE type)
Transmission Oil Capacity:
1.1 Liters (1.16 US qt)
Safety Focus:
Off-road motorcycle; primary safety features focus on handling and control rather than occupant protection.
Braking System:
Powerful hydraulic disc brakes front and rear for effective stopping power.
Suspension Design:
Advanced adjustable suspension (front forks, rear monoshock) to maintain control over varied terrain.
Frame Construction:
Robust steel frame designed for durability and stability during off-road riding.
Lighting:
Headlight and taillight for visibility, essential for trail riding and road legality where applicable.
Infotainment System:
N/A (Basic off-road motorcycle, no infotainment features)
Electronic Aids:
N/A (No electronic rider aids such as ABS or traction control)
Connectivity Features:
N/A (No integrated connectivity features)
Valve Train:
5-valve DOHC (Double Overhead Camshaft) provides excellent airflow and performance.
Cooling:
Liquid cooling system for consistent engine operating temperature, crucial for off-road performance.
Engine Oil Change:
Every 1,000 km (600 miles) or 6 months, whichever comes first. More frequently for severe use.
Oil Filter Replacement:
Replace with engine oil change.
Air Filter Cleaning:
Every 500 km (300 miles), clean and re-oil. Replace if damaged.
Spark Plug Check:
Every 1,000 km (600 miles). Check gap and condition.
Chain Lubrication Adjustment:
Every 500 km (300 miles).
Engine Oil:
Yamalube 4 (or equivalent SAE 10W-30 API SE type)
Coolant:
Permanent antifreeze coolant (50% mixture of ethylene glycol and distilled water)
Brake Fluid:
DOT 4 Brake Fluid
Carburetor Tuning:
Mikuni TM40 requires precise jetting for optimal performance across different altitudes and conditions; manual provides detailed tuning guidance.
Decompressor Lever:
Potential for wear or adjustment issues on the manual decompressor lever.
Clutch Wear:
As with most performance off-road bikes, clutch wear can occur with aggressive riding; manual details clutch inspection and replacement.
Suspension Seals:
Regular inspection and maintenance of fork and shock seals are important to prevent leaks and maintain damping performance.
Yamaha Offroad:
Yamaha has a long-standing and dominant history in off-road racing and recreation, known for performance-oriented dual-sport and motocross bikes.
Wr Series Introduction:
The WR series evolved from Yamaha's successful YZ motocross line, adapted for broader off-road use and dual-sport capabilities. The WR400F was a significant step in this evolution, offering a powerful 4-stroke engine for enduro and trail riding.
Production Period:
The WR400F was produced for a relatively short period, with the 1998-1999 models being the initial iterations before its successor, the WR426F, was introduced.
Manufacturing Location:
Typically manufactured in Japan.
