🏷️ Basic Information Identification Make: Yamaha Model: Tri-Z 250 Model Type: All-Terrain Vehicle (ATV) Category: Sport ATV Generation Production Years: 1985-1987 Codes Common Chassis Codes: 2GD (early models), 1AE (later models) 👋 Introduction Market Position Category Description: The Yamaha Tri-Z 250 was a highly regarded, high-performance sport ATV during its production run, known for its agility and powerful two-stroke engine, competing with models like the Honda TRX250R and Kawasaki Tecate-4. Competitive Analysis Key Competitors: Honda TRX250R, Kawasaki Tecate-4 (KXT250), Suzuki LT250R. Key Features Unique Selling Points: Liquid-cooled two-stroke engine, powerful acceleration, advanced suspension for its era, lightweight design, and a dedicated fanbase for its off-road capabilities. 📋 Manual Details Coverage Areas Covered Systems: • General Information • Regular Maintenance and Adjustments • Engine Maintenance and Repair • Chassis Maintenance and Repair • Electrical Troubleshooting Page Count Total Pages: 137 Manual Type Type: Service Manual / Repair Manual Language Language: English Format Format: PDF Download 📖 Manual Coverage Systems Covered Engine: Complete engine overhaul, top-end rebuild, bottom-end inspection, carburetor tuning, cooling system maintenance, lubrication system diagnostics. Transmission: Clutch operation and adjustment, gear shifting mechanisms, transmission fluid checks and changes, internal transmission component inspection. Chassis: Frame inspection, suspension tuning (front and rear), steering system overhaul, brake system maintenance (hydraulic lines, calipers, pads), wheel bearing service, swingarm and linkage lubrication. Electrical: Ignition system diagnostics, lighting circuits, charging system (stator, rectifier/regulator), battery maintenance, wiring diagrams, troubleshooting of common electrical faults. Procedures Included Maintenance: Scheduled maintenance intervals, oil changes, filter replacements (air, fuel), spark plug replacement, coolant flushes, chain adjustment and lubrication. Repair: Engine component replacement, suspension damper rebuild, carburetor cleaning and rebuilding, brake caliper servicing, electrical component diagnosis and repair. Troubleshooting: Step-by-step diagnostic procedures for common performance issues, starting problems, electrical failures, and mechanical malfunctions. Technical Depth Depth: Comprehensive, covering basic maintenance to full engine and chassis rebuilds, including detailed torque specifications and diagnostic flowcharts. 📊 Manual Specifications File Format Printability: Printable sections as needed, allowing users to print only relevant pages. Print Quality Image Resolution: High-resolution scans for clear diagrams, illustrations, and text. Binding Type Binding: Digital (PDF Download) - Not applicable for physical binding. Paper Type Paper Type: Digital (PDF Download) - Not applicable for physical paper type. ⚙️ Engine Specifications Primary Engine Engine Type: Liquid-cooled, 2-stroke, reed valve induction Displacement: 239cc (for most common models) Bore X Stroke: 68.0 mm x 64.0 mm Compression Ratio: Approx. 7.1:1 (varies slightly by year/model) Performance Horsepower: Estimated 30-35 HP (at crankshaft, depending on tuning and year) Torque: Estimated 20-23 lb-ft (at crankshaft, depending on tuning and year) Fuel System Carburetor: Mikuni VM34SS (single carburetor) Fuel Type: Unleaded gasoline (minimum 91 octane recommended), mixed with 2-stroke oil Fuel Oil Ratio: 50:1 (Yamalube 2R recommended, consult manual for alternatives) Cooling System Cooling Method: Liquid-cooled Coolant Type: Ethylene glycol-based antifreeze, 50/50 mix with distilled water Lubrication Lubrication Type: Premix (fuel/oil) and separate oil injection system for crankcase lubrication (on some models/configurations) 🔧 Transmission Standard Transmission Type: Constant-mesh 6-speed manual Clutch Type: Wet, multi-disc Features Drive System: Chain drive to rear wheel Gear Ratios: Specific ratios detailed in the manual for each gear. Transmission Fluid: Yamaha Gear Oil (or equivalent specified API GL-4, SAE 80W transmission oil) 📐 Dimensions Exterior Overall Length: Approx. 1830 mm (72.0 in) Overall Width: Approx. 765 mm (30.1 in) Overall Height: Approx. 1060 mm (41.7 in) Weights Dry Weight: Approx. 163 kg (359 lbs) Fuel Capacity: Approx. 11.0 L (2.9 US gal) Wheels Tires Front Tire Size: 21x7-10 (common) Rear Tire Size: 20x10-9 (common) Wheel Bolt Pattern: 4/110 (common, may vary slightly) 🛡️ Safety Features Ratings Crash Test Information: ATVs are not subjected to standardized crash testing like passenger vehicles. Safety is dependent on rider skill and adherence to operating guidelines. Active Features Braking System: Hydraulic disc brakes front and rear. Passive Features Chassis Design: Designed for stability and maneuverability in off-road conditions. Frame geometry and weight distribution are key to safe operation. 💡 Technology Features Infotainment Infotainment System: Not applicable. This is a performance ATV focused on mechanicals and riding dynamics, not electronic creature comforts. Driver Assistance Assistance Features: Not applicable. No electronic driver assistance features found on this model. Connectivity Connectivity Options: Not applicable. No electronic connectivity features. 🔧 Maintenance Service Intervals Oil Change Interval: Every 1000 km (600 miles) or annually, whichever comes first. Engine oil change interval for transmission oil is also crucial (consult manual for specifics). Air Filter Cleaning: Every 10-20 operating hours or as needed based on conditions. Replacement every 1-2 years. Spark Plug Replacement: Every 3000 km (1800 miles) or annually. Inspect at 1000 km (600 miles). Fluid Specifications Engine Oil Type: Yamalube 2-stroke oil (or specified equivalent meeting JASO FD or FC standards) for premix. Transmission Fluid Type: API GL-4, SAE 80W Gear Oil. Coolant Capacity: Approximately 1.5 L (1.6 US qt) Known Issues Common...