1987 Yamaha Banshee Service Manual

The 1987 Yamaha Banshee (YFZ350) is a high-performance two-stroke ATV featuring a 347cc liquid-cooled parallel-twin engine, 6-speed transmission with reverse, Yamaha Power Valve System (YPVS), Mikuni VM26SS carburetors, front dual A-arm suspension, rear swingarm suspension, and hydraulic disc brakes. This service manual covers maintenance, troubleshooting, repair procedures, and specifications for proper servicing.

1. General Information 2. Specifications 3. Periodic Maintenance 4. Engine 5. Fuel System 6. Chassis 7. Electrical System 8. Troubleshooting 9. Storage & Winterization 10. Safety Precautions

General Information

This manual provides detailed service information for the 1987 Yamaha Banshee YFZ350. Includes identification numbers, tool requirements, and general maintenance procedures.

ComponentDescription
ModelYFZ350 Banshee
Year1987
VIN LocationFrame steering head
Engine NumberRight side crankcase
Recommended ToolsStandard metric toolkit, torque wrench, compression tester
Service IntervalsRefer to maintenance schedule

Specifications

Periodic Maintenance

Regular maintenance schedule for optimal performance and longevity.

  1. Pre-ride inspection: Check tires, brakes, controls, lights
  2. Every 10 hours: Check air filter, chain tension
  3. Every 20 hours: Change transmission oil, spark plugs
  4. Every 50 hours: Clean carburetors, check brake pads
  5. Every 100 hours: Top end inspection, suspension service

WARNING! Always disconnect battery before servicing electrical components. Use proper safety equipment.

Engine

Detailed engine service procedures including disassembly, inspection, and reassembly.

ComponentTorque Specification
Cylinder Head Nuts20 ft-lbs
Spark Plugs12.5 ft-lbs
Clutch Spring Bolts7.2 ft-lbs
Flywheel Nut58 ft-lbs
Drive Sprocket Nut65 ft-lbs

Compression Test: Should read 120-150 psi per cylinder. Significant difference indicates worn rings or cylinders.

Fuel System

Carburetor adjustment and fuel system maintenance.

  1. Main Jet: #200 (standard)
  2. Pilot Jet: #25
  3. Needle Clip Position: 3rd groove
  4. Air Screw: 1.5 turns out
  5. Float Height: 21mm

Fuel Mix: 32:1 (premium gasoline to Yamalube 2R oil)

CAUTION! Always clean fuel system components in well-ventilated area. No smoking.

Chassis

Frame, suspension, and brake system maintenance.

Electrical System

Wiring diagrams, component testing, and electrical troubleshooting.

ComponentSpecification
Battery12V 10Ah
Spark PlugBR8ES (NGK)
Gap0.024-0.028 inches
Stator Resistance0.21-0.31 ohms
Ignition Coil ResistancePrimary: 0.28-0.38 ohms

Troubleshooting

SymptomPossible CauseCorrective Action
Hard startingFouled plugs, weak compressionReplace plugs, check compression
Poor performanceClogged carburetors, air filterClean carbs and air filter
OverheatingLow coolant, radiator blockageCheck coolant level, clean radiator
Transmission issuesLow oil, worn clutchCheck oil level, inspect clutch
Electrical failureBad battery, statorTest battery and charging system

Storage & Winterization

Proper storage procedures to prevent damage during extended non-use.

  1. Drain fuel from carburetors and tank
  2. Add fuel stabilizer to remaining fuel
  3. Change transmission oil
  4. Remove spark plugs and add oil to cylinders
  5. Clean and lubricate entire machine
  6. Store on stand to relieve tire pressure
  7. Disconnect battery

Safety Precautions

Always wear proper safety equipment including helmet, gloves, and eye protection. Never operate without proper training. Follow all local laws and regulations. Service should be performed by qualified technicians only.

WARNING! Engine and exhaust components become extremely hot during operation. Allow to cool before servicing.

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