1987 Yamaha Warrior 350 Repair Manual

The 1987 Yamaha Warrior 350 is a rugged ATV featuring a 348cc 4-stroke SOHC engine, 5-speed manual transmission with reverse, shaft drive, independent rear suspension, front and rear hydraulic disc brakes, and electric start. This comprehensive repair manual covers maintenance, troubleshooting, engine repair, transmission service, electrical systems, and chassis components for proper maintenance and repair procedures.

Specifications

Technical specifications for the 1987 Yamaha Warrior 350 ATV.

Maintenance Schedule

Regular maintenance intervals for optimal performance and longevity.

1. Oil Change: Every 100 hours or 6 months
2. Oil Filter: Replace with every oil change
3. Air Filter: Clean every 50 hours, replace annually
4. Spark Plug: Replace every 100 hours
5. Brake Fluid: Check monthly, replace annually
6. Drive Shaft: Lubricate every 200 hours
7. Valve Clearance: Check every 200 hours

WARNING! Always disconnect battery before maintenance. Use proper safety equipment.

Engine Repair

Complete engine disassembly, inspection, and reassembly procedures.

1. Cylinder Head Removal: Remove cam chain tensioner, cam sprocket, cylinder head bolts
2. Piston Removal: Remove cylinder, extract piston pin, remove piston rings
3. Valve Service: Remove valve springs, inspect valves and seats, lap if necessary
4. Crankshaft: Check runout, replace bearings if worn
5. Reassembly: Torque cylinder head bolts to 30 ft-lbs in crisscross pattern

CAUTION! Mark all components during disassembly for proper reassembly.

Transmission & Drive System

• Transmission Removal: Drain oil, remove shift lever, disconnect drive shaft
• Gear Inspection: Check for worn teeth, pitting, proper engagement
• Shift Mechanism: Inspect shift forks, drum, and detent mechanism
• Drive Shaft: Check universal joints for play, lubricate splines
• Final Drive: Inspect ring and pinion gears for wear patterns
• Oil Capacity: 1.7 quarts of 10W-40 motorcycle oil

Electrical System

Complete wiring diagrams and component testing procedures.

Components: CDI ignition, starter motor, voltage regulator, battery, lighting system.

Testing Procedures: Battery voltage (12.6V min), stator output (20V AC at 3000 RPM), resistance values for coils and sensors. Wiring harness inspection for chafing, corrosion, and proper connections. Fuse box location under seat, main fuse 30A, lighting fuse 10A.

Chassis & Suspension

Frame, suspension components, and steering system maintenance.

1. Frame Inspection: Check for cracks, especially around stress points
2. A-arm Bushings: Replace if worn or cracked
3. Ball Joints: Check for play, replace if excessive
4. Steering Stem: Adjust bearings, lubricate annually
5. Wheel Bearings: Check for smooth rotation, replace if rough

Tip: Use thread locker on all critical suspension fasteners.

Brake System

Hydraulic disc brake service and maintenance procedures.

1. Brake Pad Replacement: Remove caliper, extract pin, install new pads
2. Rotor Inspection: Minimum thickness 3.0mm, check for warping
3. Brake Fluid: DOT 4, bleed system annually
4. Master Cylinder: Rebuild kit available, inspect piston and seals
5. Caliper Service: Clean pistons, replace seals if leaking

WARNING! Never reuse brake fluid. Always use fresh DOT 4 fluid.

Fuel System

Carburetor service, fuel pump, and tank maintenance.

1. Carburetor Removal: Drain fuel, disconnect throttle cable and fuel line
2. Cleaning: Disassemble, clean all jets and passages with compressed air
3. Float Level: Set to 18.5mm from carburetor body
4. Fuel Filter: Replace annually or if clogged
5. Tank Cleaning: Remove and flush with fresh fuel

CAUTION! Work in well-ventilated area away from ignition sources.

Cooling System

Air cooling system maintenance and troubleshooting.

Fin Cleaning: Remove debris from cylinder and head fins. Air Flow: Ensure no obstructions around engine. Temperature Monitoring: Watch for overheating symptoms. Oil Cooler: Inspect for damage, clean external surfaces.

Troubleshooting Guide

Reset: Disconnect battery for 30 minutes to reset CDI if needed.

Service: Contact Yamaha dealer for genuine parts and technical support.