The 1988 Yamaha Warrior 350 is a high-performance ATV featuring a 348cc air-cooled four-stroke engine, 5-speed transmission with reverse, shaft drive system, dual A-arm front suspension, and swingarm rear suspension. This service manual covers complete maintenance procedures, troubleshooting, specifications, and repair instructions for proper servicing and maintenance of your Yamaha Warrior 350 ATV.
This manual provides detailed service information for the 1988 Yamaha Warrior 350 ATV. Includes identification numbers, general precautions, and special tools required for proper maintenance and repair.
| Component | Identification |
|---|---|
| Model | YFM350X Warrior |
| Frame Number | Located on right side of frame |
| Engine Number | Located on left side of crankcase |
| Manufacture Date | 1987-1988 |
| Recommended Oil | SAE 10W-30 or 10W-40 |
| Fuel Type | Regular unleaded gasoline |
| Fuel Capacity | 2.6 gallons (10 liters) |
| Oil Capacity | 2.0 quarts (1.9 liters) |
Regular maintenance schedule for optimal performance and longevity.
| Service Item | Every 6 months | Every 12 months |
|---|---|---|
| Engine Oil | Replace | Replace |
| Oil Filter | - | Replace |
| Air Filter | Clean/Replace | Clean/Replace |
| Spark Plug | Check/Clean | Replace |
| Valve Clearance | Check/Adjust | Check/Adjust |
| Brake Fluid | Check Level | Replace |
| Drive Shaft Oil | - | Replace |
| Wheel Bearings | Check | Lubricate |
WARNING! Always perform maintenance in well-ventilated area. Allow engine to cool before servicing.
Complete engine disassembly, inspection, and reassembly procedures.
Torque Specifications: Cylinder head bolts: 20 ft-lbs, Cam sprocket: 17 ft-lbs, Connecting rod: 20 ft-lbs.
Mikuni BSR33 carburetor service and fuel system maintenance.
| Component | Specification |
|---|---|
| Main Jet | #137.5 |
| Pilot Jet | #40 |
| Needle Jet | O-8 |
| Jet Needle | 5JY18-3 |
| Float Height | 17.5mm |
| Idle Speed | 1400 ± 100 rpm |
| Fuel Screw | 2 turns out |
Cleaning: Use carburetor cleaner and compressed air. Replace worn jets and gaskets.
Complete electrical system testing and component specifications.
Testing: Use multimeter for all electrical tests. Check all connections for corrosion.
Frame, suspension, and steering maintenance procedures.
Lubrication Points: Steering stem, suspension linkage, brake pedals, and clutch lever.
5-speed transmission and shaft drive service.
Clutch Adjustment: Cable free play: 10-15mm at lever end.
Hydraulic disc brake service and maintenance.
| Component | Specification |
|---|---|
| Brake Fluid | DOT 4 |
| Disc Thickness | Front: 4.0mm min, Rear: 5.0mm min |
| Pad Thickness | 1.0mm minimum |
| Caliper Piston | Check for smooth operation |
| Master Cylinder | Inspect for leaks and wear |
Bleeding: Use fresh DOT 4 fluid. Bleed until no air bubbles present.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Engine won't start | No spark, fuel, or compression | Check spark plug, fuel flow, compression (120+ psi) |
| Poor performance | Clogged carb, dirty air filter | Clean carburetor, replace air filter |
| Hard shifting | Bent shift fork, worn dogs | Inspect transmission components |
| Brakes dragging | Stuck caliper, contaminated fluid | Rebuild caliper, flush brake fluid |
| Electrical issues | Bad battery, stator, or regulator | Test charging system components |
| Overheating | Lean mixture, low oil | Check jetting, oil level and quality |
Complete electrical wiring diagrams for the 1988 Yamaha Warrior 350. Includes color-coded wires, connector locations, and component identification.
Main Harness: Shows complete routing from battery to all electrical components.
CDI System: Detailed ignition and charging circuit diagrams.
Lighting System: Headlight, taillight, and indicator circuits.
NOTE: Refer to actual manual for full-size, detailed wiring diagrams.