Market Segment:
Recreational ATV, mid-size utility segment.
Key Competitors 2004:
Honda Rancher 350, Kawasaki Prairie 360, Suzuki Eiger 400, Polaris Sportsman 400/500.
Atv Design Philosophy:
Yamaha's reputation for reliability and robust engineering in its off-road vehicles.
Target User:
Recreational riders, trail riding, light utility work.
Engine System:
Detailed disassembly, assembly, inspection, and repair procedures for the 348cc air-cooled engine.
Fuel System:
Carburetor service, fuel pump, fuel lines, fuel tank, and filter maintenance.
Electrical System:
Ignition system, lighting, starting system, charging system (stator, regulator/rectifier), battery, and wiring diagrams.
Drivetrain System:
Front differential, rear drive axle, driveshafts, and U-joints.
Transmission System:
Automatic transmission (V-belt type) service, including clutch, variator, and gearcase maintenance.
Suspension System:
Front and rear suspension components, shock absorbers, control arms, and pivot points.
Braking System:
Front and rear brake systems (hydraulic disc), brake pad replacement, caliper service, and fluid bleeding.
Steering System:
Handlebar, steering shaft, tie rods, and knuckle assembly.
Cooling System:
Air-cooling system specifics for this engine model.
Chassis Frame:
Frame inspection and repair considerations.
Bodywork Plastics:
Body panel removal and installation, fender maintenance.
Routine Maintenance:
Oil changes, filter replacements, spark plug checks, lubrication points, and general inspections.
Diagnostic Troubleshooting:
Flowcharts and symptom-based troubleshooting guides for common issues.
Component Rebuild:
Detailed instructions for engine, transmission, carburetor, and brake caliper overhauls.
Adjustment Procedures:
Carburetor adjustment, idle speed setting, and brake lever/pedal free play.
Wiring Diagrams:
Complete electrical schematics for all systems.
Specifications Data:
Torque specifications, clearances, fluid capacities, and diagnostic parameters.
Depth Level:
Comprehensive, covering everything from basic adjustments to complete engine and transmission rebuilds.
Engine Type:
4-stroke, SOHC, air-cooled
Engine Displacement:
348cc
Bore X Stroke:
83mm x 64.5mm
Power Output:
Approximately 21-23 HP (estimated, not officially published)
Torque Output:
Approximately 20-22 lb-ft (estimated)
Fuel Delivery:
Mikuni BSR33 carburetor
Fuel Type:
Unleaded gasoline (minimum 87 octane recommended)
Oil Type:
Yamalube 4 (or equivalent SAE 10W-40 or 20W-40 API SG or higher motorcycle oil)
Ignition Type:
CDI (Capacitor Discharge Ignition)
Spark Plug Type:
NGK CR6HSA (or equivalent)
Cooling Method:
Forced Air Cooling
Transmission Type:
Automatic, V-belt transmission (Yamaha Ultramatic® system)
Drive System:
2WD (Shaft drive to rear wheels)
Gear Selection:
Forward (H, L), Neutral, Reverse
Gear Oil Type:
Yamalube 4 (or equivalent SAE 10W-40 or 20W-40 API SG or higher motorcycle oil)
Gear Oil Capacity:
Approximately 0.80 Liters (800 ml) for gearcase
Overall Length:
Approx. 74.1 inches (1880 mm)
Overall Width:
Approx. 41.7 inches (1060 mm)
Overall Height:
Approx. 43.7 inches (1110 mm)
Wheelbase:
Approx. 48.8 inches (1240 mm)
Ground Clearance:
Approx. 6.5 inches (165 mm)
Dry Weight:
Approx. 478 lbs (217 kg)
Fuel Capacity:
Approx. 3.2 gallons (12 Liters), including reserve
Front Rack Capacity:
Approx. 88 lbs (40 kg)
Rear Rack Capacity:
Approx. 176 lbs (80 kg)
Atv Safety Considerations:
Standard ATV safety recommendations apply: wear helmet, eye protection, protective clothing, and follow operational guidelines.
Braking System Type:
Hydraulic disc brakes front and rear.
Handlebars:
Ergonomic handlebar design for control.
Lighting:
Dual 30W headlights, 8W taillight/stoplight.
Engine Oil Change:
Every 3,000 km (1,800 miles) or 6 months, whichever comes first.
Gear Oil Change:
Every 6,000 km (3,600 miles) or 12 months.
Air Filter Cleaning:
Every 1,000 km (600 miles) or 3 months, or more frequently in dusty conditions.
Spark Plug Replacement:
Every 6,000 km (3,600 miles) or 12 months.
Vbelt Inspection:
Inspect every 1,000 km (600 miles) or 3 months; replace as needed.
Brake Fluid Type:
DOT 3 or DOT 4 hydraulic brake fluid.
Coolant Type:
N/A (Air-cooled engine)
Common Wear Items:
V-belts, brake pads, wheel bearings, and front suspension bushings are typical wear items.
Carburetor Performance:
Mikuni BSR series carburetors can sometimes require fine-tuning or cleaning for optimal performance, especially after prolonged storage or exposure to poor fuel quality.
Starter Solenoid:
Some units may experience issues with the starter solenoid over time, requiring replacement.
Yamaha Powersports Legacy:
Yamaha has a long-standing reputation for building durable and reliable off-road vehicles, including ATVs, motorcycles, and snowmobiles, since the mid-20th century.
Bruin Lineage:
The Bruin 350 was Yamaha's entry into the mid-size utility ATV market, offering a balance of performance and comfort. It shared many components and design philosophies with other Yamaha models of its era.
Production Years Bruin 350:
Produced roughly from 2004 to 2006, before being succeeded by other models in Yamaha's lineup.
