This workshop service repair manual covers the Yamaha Moto-4 All-Terrain Vehicle (ATV) models 250 and 350, produced between 1987 and 1995. The Moto-4 was positioned as a reliable and capable utility ATV for recreational and light work applications, competing with similar models from other major manufacturers of the era. Its engineering focused on a robust chassis, dependable air-cooled four-stroke engines, and a user-friendly 5-speed manual transmission with an automatic clutch, making it a popular choice for riders seeking versatility and durability. This comprehensive English-language manual provides detailed, step-by-step instructions for all aspects of maintenance, repair, and overhaul for the Yamaha Moto-4. It covers engine, transmission, electrical systems, chassis components, and bodywork, including diagnostic procedures, troubleshooting charts, and specific maintenance schedules. The manual is designed to assist owners and technicians in performing everything from routine oil changes and filter replacements to complex engine rebuilds and electrical fault diagnosis, ensuring the longevity and optimal performance of the vehicle. 🏷️ Basic Information Identification Make: Yamaha Model: Moto-4 Sub Model: 250 & 350 Product Type: Complete Workshop Service Repair Manual Applicable Years: 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995 Vehicle Type: All-Terrain Vehicle (ATV) 👋 Introduction Market Position Positioning: The Yamaha Moto-4 series was positioned as a reliable and capable utility ATV for recreational and light work applications during its production run. Competitive Analysis Competitors: Competed against models from Honda (e.g., TRX250, TRX300), Suzuki (e.g., QuadRunner series), and Kawasaki (e.g., Bayou series) during the late 1980s and 1990s. Key Features Manual Ease Of Use: Features easy-to-follow step-by-step instructions and numerous pictures to simplify repair and maintenance tasks. Accessibility: Instant email delivery upon payment, usable on various devices (PC, Mac, tablets, smartphones). Cost Saving: Enables owners to perform their own repairs, significantly reducing labor costs. 📋 Manual Details Coverage Areas Coverage: Comprehensive; All Models/Engines/Trim/Transmissions Types Covered Page Count Page Count: Undisclosed (estimated to be extensive due to 'A-Z' coverage) Manual Type Type: Workshop Service Repair Manual Language Language: English Format Format: Downloadable Digital Format (PDF compatible) 📖 Manual Coverage Systems Covered Engine: Engine overhaul, disassembly, assembly, tuning, diagnostics, lubrication system, cooling system, fuel system, exhaust system. Transmission: Transmission overhaul, disassembly, assembly, clutch service, gearbox repair, final drive. Electrical: Ignition system, starting system, charging system, lighting system, wiring diagrams, battery service, troubleshooting electrical faults. Chassis: Frame, suspension (front and rear), steering system, wheels, tires, brakes (front and rear). Bodywork: Body panels, fenders, seat, controls, decals, general maintenance. Troubleshooting: Diagnostic procedures for common and uncommon issues, fault finding charts. Procedures Included Maintenance: Scheduled maintenance, oil changes, filter replacements, chain lubrication and adjustment, brake pad inspection, tire pressure checks. Repair: Complete repair procedures for all major and minor components, from engine rebuilds to electrical system fixes. Disassembly Assembly: Detailed step-by-step instructions for taking apart and putting back together all vehicle systems and components. Tuning Adjustment: Carburetor tuning, ignition timing adjustments, suspension adjustments. Technical Depth Depth: Comprehensive; suitable for both novice DIY mechanics and experienced technicians. Covers basic maintenance to complex engine and transmission rebuilds. 📊 Manual Specifications File Format File Format: PDF (requires Adobe Reader) Print Quality Print Quality: High Quality (printable pages) Binding Type Binding Type: N/A (Digital Download) Paper Type Paper Type: N/A (Digital Download) ⚙️ Engine Specifications Primary Engine 250 Engine Type 250: Four-stroke, SOHC, air-cooled Displacement 250: 230cc - 246cc (exact figure varies by specific model year revision) Bore X Stroke 250: Approximately 69mm x 64mm (typical for this displacement class, specific values in manual) Compression Ratio 250: Around 9.2:1 to 10.2:1 (manual will specify exact) Primary Engine 350 Engine Type 350: Four-stroke, SOHC, air-cooled Displacement 350: 348cc - 350cc (exact figure varies by specific model year revision) Bore X Stroke 350: Approximately 80mm x 69mm (typical for this displacement class, specific values in manual) Compression Ratio 350: Around 8.4:1 to 9.2:1 (manual will specify exact) Performance Horsepower Estimate 250: Approx. 16-20 HP (manual will provide precise figures) Horsepower Estimate 350: Approx. 22-26 HP (manual will provide precise figures) Fuel System Carburetor: Single Mikuni carburetor (specific model number provided in manual for both 250 and 350 variants). Fuel Type: Unleaded gasoline (manual specifies octane rating requirement). 🔧 Transmission Standard Transmission Type: 5-speed manual transmission with automatic clutch (sometimes referred to as a 'semi-automatic' or 'wet multi-plate' clutch). Drive System: Shaft drive (2WD). Reverse: Yes (typically integrated into the transmission). Features Clutch Type: Automatic centrifugal clutch. Gear Ratios: Specific gear ratios for each gear and reverse are detailed in the manual. Fluid Specifications Transmission Oil Type: Yamaha recommends specific API SG or SH, SAE 10W-40 or 20W-40 viscosity motor oil (confirm with manual). 📐 Dimensions Exterior General Length Estimate: Approx. 75-80 inches (specific dimensions provided in manual). Width Estimate: Approx. 40-45 inches (specific dimensions provided in manual). Height Estimate: Approx. 40-45 inches (specific dimensions provided in manual). Weights Dry Weight Estimate: Approx. 400-450...