Segment:
Entry-level to mid-range utility ATV segment.
Target Audience:
Recreational riders, farmers, and light-duty utility users.
Key Competitors:
Honda FourTrax 350, Suzuki Eiger 400, Polaris Sportsman 400.
Feature 1:
Reliable 348cc air-cooled engine known for its durability.
Feature 2:
Selectable 2WD/4WD system for versatile traction control.
Feature 3:
Independent front suspension (IFS) for improved ride comfort and handling.
Feature 4:
Automatic centrifugal clutch with V-belt transmission for ease of operation.
Systems Covered:
Engine, Transmission, Drivetrain (4WD), Suspension, Steering, Brakes, Electrical System, Fuel System, Cooling System, Chassis, Bodywork, Maintenance, Troubleshooting, Diagnostics
Estimated Page Count:
300+
Type:
Factory Service Manual (FSM)
Engine System:
Detailed breakdown of the 348cc air-cooled engine, including cylinder head, valve train, piston, crankshaft, lubrication system, and timing components.
Drivetrain System:
Comprehensive coverage of the 2WD/4WD engagement system, front differential, rear differential, drive shafts, and U-joints.
Electrical System:
Wiring diagrams, ignition system, lighting, charging system (stator, regulator/rectifier), starter motor, battery maintenance, and troubleshooting for electrical faults.
Maintenance Procedures:
Scheduled maintenance intervals, oil changes, filter replacements, spark plug service, air filter cleaning/replacement, brake fluid flush, coolant checks, lubrication points.
Troubleshooting Guides:
Systematic diagnostic charts and procedures for identifying and resolving common issues, including starting problems, engine performance issues, electrical faults, and drivetrain malfunctions.
Repair Procedures:
Step-by-step instructions for disassembly, inspection, repair, and reassembly of all major vehicle components, including engine rebuilds, transmission overhaul, suspension component replacement, and brake system servicing.
Diagnostic Capability:
Advanced diagnostic procedures, including specifications for ignition timing, fuel mixture analysis, and electrical system testing using multimeters and specialized tools.
Rebuild Capability:
Complete engine and transmission rebuild procedures, including torque specifications, critical clearances, and component tolerances for ensuring proper assembly and longevity.
โ๏ธ Engine Specifications
Engine Type:
4-stroke, SOHC, air-cooled
Bore X Stroke:
83mm x 64.5mm
Horsepower Rating Approx:
19.7 HP @ 6500 RPM (Estimate based on similar models)
Torque Rating Approx:
20.1 lb-ft @ 5500 RPM (Estimate based on similar models)
Fuel Delivery:
Mikuni BSR33 carburetor
Fuel Type:
Unleaded gasoline, 87 octane minimum
Fuel Tank Capacity:
3.2 gal (12 L)
Type:
Automatic (Yamaha Ultramaticยฎ Transmission - CVT)
Drive System:
Shaft Drive
Gear Reduction:
High/Low range with reverse
Engine Braking:
Utilizes centrifugal clutch and V-belt for effective engine braking.
Transmission Oil Type:
Yamalube 4 (or equivalent 20W-40 API SG or higher)
Transmission Oil Capacity:
Approx. 1.6 L (1.7 US qt) for engine oil, including filter
Atv Safety Standards:
Compliant with ANSI/SVIA standards
Braking System:
Hydraulic disc brakes front and rear.
Parking Brake:
Parking brake lever integrated with rear brake caliper.
Lighting:
Dual 30W halogen headlights, 5/21W taillight/brake light.
Operator Safety:
Thumb throttle for controlled acceleration, handlebar grips for secure control.
Display:
Digital LCD meter displaying speedometer, odometer, tripmeter, clock, 4WD indicator, neutral/reverse indicator.
Traction Control:
Selectable 2WD/4WD system allows the operator to choose the appropriate traction for the terrain.
Charging Port:
Optional accessory charging port may be available, check specific model configuration.
Engine Oil Change:
Every 1000 km (600 miles) or 6 months, whichever comes first. First service at 100 km (60 miles) or 1 month.
Air Filter Check:
Every 200 km (120 miles) or 1 month. Clean/replace as needed, more frequently in dusty conditions.
Spark Plug Replacement:
Every 5000 km (3000 miles) or 2 years. Check gap every 1000 km (600 miles).
Engine Oil Specification:
Yamalube 4 (20W-40) API SG or higher.
Coolant Type:
Permanent type antifreeze/coolant (ethylene glycol based) with a 50/50 mix of water.
Brake Fluid Type:
DOT 3 or DOT 4 hydraulic brake fluid.
Common Wear Item:
V-belt in CVT transmission can wear over time and require replacement. Check for signs of fraying or glazing.
Potential Problem 1:
Carburetor can become gummed up if fuel sits for extended periods. Fuel stabilizer recommended for storage.
Potential Problem 2:
4WD engagement system components (actuator, hub mechanisms) may require cleaning and lubrication to ensure proper operation.
Electrical Concern:
Corrosion on electrical connectors can lead to intermittent issues. Regular inspection and dielectric grease application is beneficial.
Manufacturer:
Yamaha Motor Corporation, established 1955, known for musical instruments and a long history in powersports.
Bruin Lineage:
The Bruin line was Yamaha's mid-size utility ATV offering, evolving from earlier models and paving the way for newer Grizzly and Kodiak generations.
2004 Updates:
The 2004 model continued to refine the reliable platform, offering a balance of power, comfort, and utility.
Manufacturing Location:
Primarily manufactured in Japan or with components sourced from Yamaha's global supply chain.
๐ Awards & Recognition
Industry Awards:
While specific awards for the 2004 Bruin 350 4WD are not widely publicized, Yamaha ATVs have consistently received praise for reliability and performance in their respective segments.
User Reviews:
Typically rated highly by users for its robust engine, comfortable ride, and dependable 4WD system for utility tasks and recreational trail riding.
