Target Audience:
Owners and technicians performing maintenance and repairs on the Yamaha Moto-4 250.
Competitors:
This manual targets owners of specific Yamaha models, competing with other OEM service manuals and aftermarket repair guides for similar ATVs of the era.
Manual Benefits:
Provides factory-level detail for DIY repairs, reducing reliance on expensive dealership service. Enhances longevity and performance of the ATV.
Support:
Free replacement offered for lost manuals, enhancing customer value and trust.
Engine:
Engine disassembly, assembly, rebuilding, internal components (piston, conrod, crankshaft, camshaft, valves, cylinder, jug), ignition system, stator, magneto, fuel pump, carburetion (carburetor, jets, mixture screw), cooling system.
Transmission:
Transmission overhaul, gearshift mechanism, primary reduction gear, clutch, shaft drive.
Chassis:
Frame, swingarm, suspension (struts, springs), front forks, steering system, handle bars.
Brakes:
Brake system inspection, adjustment, component replacement, hydraulic systems.
Electrical:
Charging system (rectifier, regulator), starting system (starter motor, kick starter), lighting, switches, battery, coil, troubleshooting electrical issues (e.g., no spark).
Bodywork:
Plastics, fenders, body panels, seat, fuel tank.
Maintenance:
Scheduled maintenance, fluid changes (oil, coolant), filter replacement, spark plug service, valve clearance adjustment, tire pressure checks, lubrication.
Troubleshooting:
Diagnosis of common problems, error code interpretation (if applicable), no-start conditions, performance issues.
Repair:
Step-by-step instructions for disassembly, repair, and reassembly of all major vehicle components and systems.
Installation:
Guidance for installing replacement parts or accessories.
Depth:
Comprehensive, from basic maintenance and troubleshooting to complete engine and transmission overhauls.
Detail Level:
Includes detailed part diagrams, torque specifications, clearances, and step-by-step rebuild instructions.
Engine Type:
4-stroke, air-cooled, SOHC, 2-valve
Displacement:
230 cc (approximate, based on model designation)
Bore X Stroke:
Refer to manual for exact specifications (typically around 68mm x 64mm for this class)
Compression Ratio:
Refer to manual for exact specifications (typically around 8.5:1 - 9.5:1)
Horsepower:
Refer to manual for exact specifications (estimated 15-20 HP)
Torque:
Refer to manual for exact specifications
Carburetor:
Mikuni (specific model to be confirmed in manual, e.g., VM26)
Fuel Type:
Unleaded gasoline
Fuel Tank Capacity:
Refer to manual for exact specifications (typically 2.5-3.5 gallons)
Engine Oil Type:
Yamalube or equivalent SAE 10W-30 or 20W-40 API SG or higher (specific viscosity may vary by temperature, refer to manual)
Oil Capacity:
Refer to manual for exact specifications (typically around 1.6-1.8 liters)
Length:
Refer to manual for exact specifications
Width:
Refer to manual for exact specifications
Height:
Refer to manual for exact specifications
Dry Weight:
Refer to manual for exact specifications (typically around 450-500 lbs)
Curb Weight:
Refer to manual for exact specifications
Load Capacity:
Refer to manual for exact specifications
Engine Oil Change:
Every 1000 km or 6 months (refer to manual for exact interval and conditions).
Air Filter Cleaning:
Regularly check and clean, replace as needed based on operating conditions (e.g., dusty environments).
Spark Plug Service:
Inspect and clean or replace at specified intervals (refer to manual).
Valve Clearance Check:
At initial break-in and then at regular intervals (e.g., every 2000-3000 km).
Brake Fluid:
DOT 3 or DOT 4 brake fluid (refer to manual for confirmation).
Coolant:
Ethylene glycol-based antifreeze and water mixture (50/50 ratio recommended). Refer to manual for specific type and capacity.
Carburetor Tuning:
Carburetor can become out of tune over time, requiring cleaning and adjustment of idle speed and mixture.
Electrical Connections:
Corrosion or loose connections in the electrical system can cause intermittent issues.
Suspension Wear:
As with any older ATV, suspension bushings and shocks may require servicing or replacement.
Yamaha Atv Legacy:
Yamaha has a long history of innovation in the ATV market, beginning with the highly influential Tri-Z and Warrior models.
Moto4 Lineup:
The Moto-4 series was Yamaha's primary utility and recreational ATV offering during the late 1980s and early 1990s, known for its robust construction and reliability.
Manufacturing Location:
Likely manufactured in Japan or North America by Yamaha Motor Corporation.