Production Years Covered:
2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
Engine Code General:
400cc Single-Cylinder, Four-Stroke
Positioning:
Essential technical resource for owners and technicians seeking to perform maintenance and repairs on the Yamaha WR400F.
Value Proposition:
Provides dealership-level information, enabling cost savings and informed DIY repairs, replicating the expertise found in authorized service centers.
Unique Selling Points:
Comprehensive coverage, detailed procedures, inclusion of proprietary component information, and emphasis on safety and accuracy.
Engine:
Complete overhaul and repair procedures
Transmission:
Complete disassembly and assembly procedures
Fuel System:
Detailed diagnosis and repair of fuel delivery and control
Ignition System:
Ignition timing, component testing, and troubleshooting
Lubrication System:
Lubrication schedules, component inspection, and repair
Exhaust System:
Repair and maintenance of exhaust components
Electrical System:
Wiring diagrams, component testing, and troubleshooting
Body:
Body panel repair, fitment, and component replacement
Routine Maintenance:
Tune-ups, oil changes, filter replacements
Removal Installation:
Step-by-step guides for component removal and installation
Assembly Disassembly:
Detailed instructions for dismantling and reassembling major components
Diagnostic Troubleshooting:
Procedures for identifying and resolving faults
Proprietary Component Repair:
Guidance for specific branded parts
Depth:
Comprehensive (from routine maintenance to full engine/transmission rebuilds)
Intended User:
Mechanical Technicians familiar with BRP products and general automotive practices
Engine Type:
Liquid-cooled, 4-stroke, DOHC, 5-valve
Displacement:
399cc (Exact displacement may vary slightly by sub-model or tuning)
Bore X Stroke:
84.0 mm x 72.0 mm (Typical for this generation)
Compression Ratio:
11.4:1 (Typical)
Horsepower:
Estimated 40-45 HP (At crankshaft, depending on tuning and exhaust)
Torque:
Estimated 35-38 Nm (At crankshaft, depending on tuning and exhaust)
Carburetor:
Mikuni BSR38 (Typical, may vary by specific market or model year)
Fuel Type:
Unleaded gasoline (Octane rating specified in manual)
Ignition System Type:
TCI (Transistor Controlled Ignition)
Length:
Approx. 2,200 mm (Varies by model year)
Width:
Approx. 820 mm (Varies by model year)
Height:
Approx. 1,250 mm (Varies by model year)
Dry Weight:
Approx. 118 kg (Varies by model year)
Wet Weight:
Approx. 125 kg (Varies by model year, with all fluids)
Front Tire Size:
80/100-21 (Typical, check manual for specifics)
Rear Tire Size:
110/90-18 (Typical, check manual for specifics)
Safety Features Emphasis:
Manual stresses use of safety equipment and adherence to precautions.
Braking System:
Hydraulic disc brakes, front and rear
Warning Symbols:
Highlights WARNING, CAUTION, and NOTE designations for critical information.
Oil Change Interval:
Refer to manual for specific mileage/hour intervals; typically 1000-1500 miles or 30-50 hours for competitive use.
Air Filter Cleaning:
Frequent cleaning recommended, especially in dusty conditions; covered in detail.
Engine Oil Type:
Yamalube or equivalent API SG, SAE 10W-40 or 20W-40 (specific viscosity depends on ambient temperature, consult manual).
Engine Oil Capacity:
Refer to manual, typically around 1.5-1.8 liters for engine lubrication and transmission.
Coolant Type:
Yamaha's recommended mixture of ethylene glycol-based coolant and distilled water (50/50 ratio).
Brake Fluid Type:
DOT 4 brake fluid.
Common Wear Items:
Clutch wear, valve stem seals, cam chain tensioner, carburetor jetting adjustments for altitude/conditions.
Typical Maintenance Tasks:
Regular cleaning and re-oiling of air filter, chain lubrication and adjustment, spark plug inspection, valve clearance checks.
Tool Requirement:
Manual refers to specific Yamaha WR400F special tool numbers for certain adjustments and repairs, often illustrated.
Torque Wrench:
Essential for ensuring fasteners are tightened to specification.
Yamaha Motorcycles:
Yamaha has a long-standing reputation for performance-oriented motorcycles, particularly in off-road and motocross disciplines.
Wr Series Development:
The WR series represents Yamaha's lineage of competitive enduro motorcycles, often derived from their YZ motocross platforms, adapted for off-road legal use and longer-distance riding.
Production Period Overview:
The WR400F was a significant model in the late 1990s and early 2000s, bridging the gap between pure motocross and dedicated enduro machines.
