🏷️ Basic Information Identification Make: Yamaha Model: YFM400 Big Bear Model Code: YFM400FWA(M) Vehicle Type: All-Terrain Vehicle (ATV) Generation Generation Designation: Fourth Generation Big Bear Codes Chassis Code: YFM400FWA(M) 👋 Introduction Market Position Atv Segment: Utility ATV Target User: Recreational riders, hunters, farmers, and those needing a dependable workhorse. Competitive Analysis Key Competitors: Honda Foreman, Kawasaki Prairie, Polaris Sportsman. Key Features Model Highlights: Known for its ruggedness, reliability, selectable 4WD, and comfortable ride. Manual Value Proposition: Provides the essential technical knowledge for owners and technicians to maintain and repair the YFM400 Big Bear, ensuring longevity and optimal performance. 📋 Manual Details Coverage Areas Manual Title: ATV Yamaha YFM400 Bigbear (YFM400FWA(M)) Complete Factory Service / Repair / Workshop Manual Manual Scope: Complete Factory Service, Repair, and Workshop Page Count Estimated Page Count: Approximately 500+ pages (based on typical factory manuals for this era and complexity) Manual Type Manual Type: Factory Service Manual / Workshop Manual Language Language: English Format Digital Format: PDF Download 📖 Manual Coverage Systems Covered Engine Systems: Engine overhaul, disassembly, assembly, lubrication, cooling system, ignition system, fuel system (carburetor tuning and maintenance), exhaust system, emissions control. Transmission Drivetrain: Automatic transmission (CVT), gearcase, drive shafts, differentials (if applicable), clutches, maintenance, and repair procedures. Chassis Suspension: Frame inspection and repair, front and rear suspension (A-arms, shocks, bushings), steering system (handlebar, steering shaft, tie rods). Braking System: Front and rear brake calipers, master cylinders, brake lines, hydraulic fluid specifications, bleeding procedures, pad replacement, rotor inspection. Electrical System: Wiring diagrams, battery maintenance, charging system (stator, rectifier/regulator), lighting system (headlights, taillights, indicators), starting system (starter motor, solenoid), CDI unit, sensors. Bodywork Plastics: Fender removal and installation, seat removal, fuel tank and shroud maintenance, handlebar assembly, grip replacement. Procedures Included Routine Maintenance: Oil and filter changes, air filter cleaning/replacement, spark plug replacement, lubrication points, chain/belt adjustment (if applicable), brake adjustments. Troubleshooting: Diagnostic charts, common problem identification (e.g., starting issues, poor performance, electrical faults), symptom-based troubleshooting guides. Repair Overhaul: Detailed step-by-step instructions for component disassembly, inspection, repair, and reassembly of major systems like the engine, transmission, and suspension. Special Tools: Identification and usage of specialized tools required for specific repair procedures. Technical Depth Diagnostic Capabilities: Advanced diagnostics for engine performance issues, electrical system faults, and drivetrain problems. Rebuild Procedures: Comprehensive guides for full engine rebuilds, transmission overhauls, and suspension component replacement. Specifications Tolerances: Precise technical data including torque specifications, clearances, tolerances, fluid capacities, and electrical resistance values. 📊 Manual Specifications File Format File Format: PDF Print Quality Image Resolution: High resolution for clear diagrams and text. Text Searchability: Searchable text for quick information retrieval. Binding Type Binding Type Digital: N/A (Digital PDF) Paper Type Paper Type Digital: N/A (Digital PDF) ⚙️ Engine Specifications Primary Engine Engine Type: 4-stroke, SOHC, air-cooled Displacement: 387 cc Bore X Stroke: 82.0 mm x 71.5 mm Compression Ratio: 8.8:1 Valve Clearance Intake Cold: 0.09 - 0.14 mm (0.0035 - 0.0055 in) Valve Clearance Exhaust Cold: 0.12 - 0.17 mm (0.0047 - 0.0067 in) Performance Horsepower Estimated: Approx. 21 HP @ 5500 RPM (Industry standard, specific Yamaha figures may vary slightly) Torque Estimated: Approx. 24 lb-ft @ 4000 RPM (Industry standard, specific Yamaha figures may vary slightly) Fuel System Fuel Delivery: Carburetor Carburetor Model: Mikuni BSR33/1 Fuel Type: Unleaded gasoline Fuel Octane Rating: 87 AKI (Octane Rating) Fuel Tank Capacity: 13.5 L (3.57 gal) Lubrication Engine Oil Type: Yamalube 4 (or equivalent SAE 10W-40, API SG or higher) Engine Oil Capacity W Filter: 2.20 L (2.32 US qt) Engine Oil Capacity Wo Filter: 2.00 L (2.11 US qt) Cooling System Cooling Method: Air-cooled Ignition System Ignition System: CDI (Capacitor Discharge Ignition) Spark Plug Type: NGK CR6HSA / DENSO U20FSR-U Spark Plug Gap: 0.6 - 0.7 mm (0.024 - 0.028 in) 🔧 Transmission Standard Transmission Type: Automatic Continuously Variable Transmission (CVT) Drive System: Shaft drive, Selectable 4WD with 2WD/4WD switch Features Gear Reduction Ratio Low: 3.596:1 Gear Reduction Ratio High: 2.888:1 Final Drive: Bevel gear and drive shaft Fluid Specifications Gearcase Oil Type: Yamalube Gear Oil (or SAE 80 hypoid gear oil) Fluid Capacities Gearcase Oil Capacity: 0.42 L (0.44 US qt) 📐 Dimensions Exterior Length: 2030 mm (79.9 in) Width: 1095 mm (43.1 in) Height: 1170 mm (46.1 in) Wheelbase: 1280 mm (50.4 in) Ground Clearance: 250 mm (9.8 in) Weights Dry Weight: 262 kg (578 lbs) Wet Weight Estimated: 274 kg (604 lbs) (Approx. with full fluids) Cargo Front Rack Capacity: 20 kg (44 lbs) Rear Rack Capacity: 40 kg (88 lbs) Wheels Tires Front Tire Size: AT25x8-12 Rear Tire Size: AT25x10-12 Front Wheel Size: 12 x 7.0 AT Rear Wheel Size: 12 x 8.0 AT Bolt Pattern Wheels: 4/110mm 🛡️ Safety Features Ratings Safety Certification: Meets ANSI standards for recreational ATVs (American National Standards Institute). Active Features Braking System Type: Hydraulic disc brakes, front and rear. Parking Brake: Handlebar-mounted...
Known for its ruggedness, reliability, selectable 4WD, and comfortable ride.
Manual Value Proposition:
Provides the essential technical knowledge for owners and technicians to maintain and repair the YFM400 Big Bear, ensuring longevity and optimal performance.
Frame inspection and repair, front and rear suspension (A-arms, shocks, bushings), steering system (handlebar, steering shaft, tie rods).
Braking System:
Front and rear brake calipers, master cylinders, brake lines, hydraulic fluid specifications, bleeding procedures, pad replacement, rotor inspection.
Electrical System:
Wiring diagrams, battery maintenance, charging system (stator, rectifier/regulator), lighting system (headlights, taillights, indicators), starting system (starter motor, solenoid), CDI unit, sensors.
Bodywork Plastics:
Fender removal and installation, seat removal, fuel tank and shroud maintenance, handlebar assembly, grip replacement.
Procedures Included
Routine Maintenance:
Oil and filter changes, air filter cleaning/replacement, spark plug replacement, lubrication points, chain/belt adjustment (if applicable), brake adjustments.
Troubleshooting:
Diagnostic charts, common problem identification (e.g., starting issues, poor performance, electrical faults), symptom-based troubleshooting guides.
Repair Overhaul:
Detailed step-by-step instructions for component disassembly, inspection, repair, and reassembly of major systems like the engine, transmission, and suspension.
Special Tools:
Identification and usage of specialized tools required for specific repair procedures.
Technical Depth
Diagnostic Capabilities:
Advanced diagnostics for engine performance issues, electrical system faults, and drivetrain problems.
Rebuild Procedures:
Comprehensive guides for full engine rebuilds, transmission overhauls, and suspension component replacement.
Specifications Tolerances:
Precise technical data including torque specifications, clearances, tolerances, fluid capacities, and electrical resistance values.
📊 Manual Specifications
File Format
File Format:
PDF
Print Quality
Image Resolution:
High resolution for clear diagrams and text.
Text Searchability:
Searchable text for quick information retrieval.
Binding Type
Binding Type Digital:
N/A (Digital PDF)
Paper Type
Paper Type Digital:
N/A (Digital PDF)
⚙️ Engine Specifications
Primary Engine
Engine Type:
4-stroke, SOHC, air-cooled
Displacement:
387 cc
Bore X Stroke:
82.0 mm x 71.5 mm
Compression Ratio:
8.8:1
Valve Clearance Intake Cold:
0.09 - 0.14 mm (0.0035 - 0.0055 in)
Valve Clearance Exhaust Cold:
0.12 - 0.17 mm (0.0047 - 0.0067 in)
Performance
Horsepower Estimated:
Approx. 21 HP @ 5500 RPM (Industry standard, specific Yamaha figures may vary slightly)
Torque Estimated:
Approx. 24 lb-ft @ 4000 RPM (Industry standard, specific Yamaha figures may vary slightly)
Fuel System
Fuel Delivery:
Carburetor
Carburetor Model:
Mikuni BSR33/1
Fuel Type:
Unleaded gasoline
Fuel Octane Rating:
87 AKI (Octane Rating)
Fuel Tank Capacity:
13.5 L (3.57 gal)
Lubrication
Engine Oil Type:
Yamalube 4 (or equivalent SAE 10W-40, API SG or higher)