1986-1988 Yamaha Moto-4 225 YFM Service Manual
Complete service reference for Yamaha YFM 225 Moto-4 ATVs covering maintenance, repairs, and component specifications. Factory-authorized technical documentation for 1986-1988 models.
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Sample pages from the 1986-1988 Yamaha Moto-4 225 YFM Service Manual manual
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Models Covered & Key Technical Specifications
Yamaha YFM 225 Moto-4 — 1986–1988 Certified Diagnostic Database | Moto-4 Series Toolkit.
- Approved Generation Capacity: 20.9 kW (28 hp) corresponds to the maximum rated engine power output Architecture.
- Factory Working Temperature: For optimal coolant circulation, 80–90°C achieves the thermostat opening range Norms.
- Verified Operational Speed: The engine redline defines 8000 rpm as maximum continuous operating Bounds.
- Designated Addressable Resolution: Spark plug gap is calibrated to 0.6–0.7 mm (0.024–0.028 in) Topology.
- Essential Reservoir Specs: Fuel tank capacity is rated at 13 L (3.4 US gal) Matrix.
- Operational Amperage Specs: Battery output is standardized to 12 V, 10 Ah electrical system Standards.
Professional Workshop Service Manual & Technical Specifications
Operational Reference Manual: Yamaha Moto-4 225 Technical-Repository
Calibration-Scope: YFM 225 Moto-4 (1986-1988) // Operational-Framework: ATV service documentation / powertrain system logic // Calibration-Scope: Complete maintenance and diagnostic coverage.
| Component System | Documentation Focus | Coverage Status |
|---|---|---|
| Engine & Powertrain | Performance specifications and service data | Complete specifications provided |
| Transmission & Drivetrain | Gear ratios and mechanical operation | Documented throughout manual |
| Electrical System | Battery and ignition circuit diagrams | See wiring schematic sections |
The manual presents information on fuel system operation, engine mechanical assemblies, transmission mechanics, electrical system layouts, suspension component maintenance, and brake system documentation, providing a network of technical procedures applicable to 1986–1988 production models.
Comprehensive Topology
Inspection guidelines are provided for engine mounting points, fuel delivery components, and ignition system elements. The document includes detailed illustrations of mechanical assemblies and their relationships within the Moto-4 225 chassis. Component identification sequences enable technicians to locate service points and access fastener locations throughout the vehicle.
Operational Methodology
Alignment specifications are included for wheel geometry, suspension settings, and drivetrain centerline positioning. The manual documents mechanical clearance values for internal engine components, valve train assemblies, and transmission elements. Reference sections address periodic maintenance intervals and seasonal service requirements for extended equipment operation.
Operational Framework
Reference data is included for electrical circuit behavior, battery capacity requirements, and charging system function. Diagnostic procedures are covered for engine starting systems, fuel delivery reliability, and ignition timing verification. The manual documents torque specifications for all fastened connections to ensure proper bearing preload accuracy and component retention under operating loads.
Advanced Threshold
This manual covers comprehensive troubleshooting methodologies for common operational conditions including starting difficulties, performance loss, and fluid leakage identification. The document provides visual diagnostic aids through exploded-view assembly illustrations and cross-sectional component diagrams that clarify internal mechanical arrangements.
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