Yamaha YFM250W Moto-4 ATV Service Manual - Precision Maintenance, Diagnostics & Repairs, 1989-1991
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Sample pages from the Yamaha YFM250W Moto-4 ATV Service Manual - Precision Maintenance, Diagnostics & Repairs, 1989-1991 manual
Purchase Information
Technical Specifications
- Document Number / Seller:
- 28754 / Brian Wright
- File Size:
- 60.66 MB
- File Type:
- Language:
- English
- Pages:
- 320
- Printable:
- Yes
- Estimated Download Time:
- 1.24 Minutes
- Delivery Format:
- Digital (PDF) - Instant Access
- Category:
- ATV
- Brand:
- Yamaha
- Reviewed and Approved:
- Dec 26, 2025
Yamaha Models and Parts Covered in this ATV Manual
- YFM250W Moto-4 (1989)
- YFM250W Big Bear 250 (1989)
Complete Manual Information
Yamaha Moto-4 250 / YFM250W Professional Service Manual 1989-1991
Keep your Yamaha ATV in peak condition with this definitive, professional-grade service manual. Covering the iconic 1989-1991 Yamaha YFM250W (widely known as the Moto-4 250), this guide is the exact same resource used by certified Yamaha technicians. Whether you are a weekend warrior performing routine maintenance or a pro-mechanic tackling a full engine overhaul, this manual provides the technical precision required for a job well done.
Comprehensive Model Coverage & Identification
This manual is specifically designed for the YFM250W series. To ensure you have the correct documentation for your specific machine, verify your Vehicle Identification Number (VIN) or Engine Serial Number against the factory starting sequences listed below:
- USA Models: Starting VIN JY43GHA0 * KC000101 (Engine: 3GH-000101)
- Canadian (CDN) Models: Starting VIN JY43GHW0 * KC047101 (Engine: 3GH-047101)
- International Models (Europe, AUS, NZ, ZA): Starting Frame 3GH-047101 (Engine: 3GH-047101)
Expert Technical Specifications
This manual goes far beyond basic oil changes. It includes exhaustive data for every critical system:
- Engine: 229.6cc air-cooled 4-stroke SOHC, forward-inclined single cylinder.
- Tuning Specs: Exact valve clearances (Intake: 0.05-0.09mm, Exhaust: 0.11-0.15mm) and idle speeds (1,450–1,550 r/min).
- Torque Values: Complete fastener tables, including cylinder head bolts (22 Nm) and the critical rear axle nut three-step tightening sequence (up to 240 Nm).
- Fluid Capacities: Precise measurements for periodic oil changes (2.1L) and final gear case service (0.21L).
Detailed Chapter Breakdown
- General Information: Model identification, essential shop safety, and a guide to specialized Yamaha service tools.
- Periodic Inspection & Adjustment: A complete maintenance schedule to ensure long-term reliability and prevent costly repairs.
- Engine Overhaul: Step-by-step teardown and reassembly of the top and bottom end, including piston, crankshaft, and balancer shaft service.
- Carburetion: Comprehensive cleaning and adjustment procedures for the Mikuni VM24SH carburetor, including float height and jetting specs.
- Drive Train: Detailed service for the sub-transmission, shaft drive system, and final gear shimming procedures.
- Chassis & Suspension: Service guides for the steering system, front drum brakes, rear disc brakes, and shock absorber adjustments.
- Electrical System: Complete wiring diagrams, CDI ignition troubleshooting, and starter motor overhaul instructions.
- Troubleshooting: A dedicated 9th chapter designed to help you quickly diagnose starting failures, poor performance, or handling instabilities.
Real Value for the DIY Owner
Stop guessing and start fixing with confidence. This manual features clear sectional views, exploded diagrams, and detailed cable routing maps. By following the factory-recommended procedures, you reduce the risk of damaging expensive components and ensure your Yamaha Moto-4 remains a reliable workhorse for years to come. From checking the battery specific gravity (1.280 at 68°F) to adjusting the speed limiter for beginner riders, every detail is covered.
Download Instructions for Yamaha ATV Manual
Frequently Asked Questions - Yamaha ATV Manual
Is this manual suitable for beginners?
Yes, this Yamaha manual is designed for both professional technicians and DIY enthusiasts. It includes step-by-step procedures with clear illustrations and safety guidelines for ATV maintenance and repair.
What file format will I receive?
You will receive this manual as a PDF file (60.66 MB), which is compatible with all devices. The manual is fully searchable and printable for your convenience.
How quickly can I access the manual after purchase?
You'll receive instant access to your Yamaha ATV manual immediately after payment completion. The download link is valid for 3 days, with lifetime re-download guarantee.
Can I print specific sections of the manual?
Absolutely! This digital manual allows you to print any section you need, from individual pages to complete chapters, making it perfect for workshop use.
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