1986 Yamaha Moto 4 225 Service Manual

The 1986 Yamaha Moto 4 225 is a four-wheel ATV featuring a 223cc air-cooled four-stroke engine, electric start with pull-start backup, shaft drive system, full floorboards, front and rear racks, and dual-range transmission. This service manual covers maintenance procedures, troubleshooting, specifications, and repair instructions for proper operation and longevity of your ATV. Below are key sections for safety, maintenance schedules, engine service, transmission, electrical system, and troubleshooting.

1. Specifications 2. Safety Precautions 3. Maintenance Schedule 4. Engine Service 5. Fuel System 6. Electrical System 7. Transmission & Drive 8. Brake System 9. Suspension & Steering 10. Troubleshooting 11. Wiring Diagrams

Specifications

Technical specifications for the 1986 Yamaha Moto 4 225 ATV.

Component	Specification
Engine Type	223cc air-cooled 4-stroke SOHC
Bore x Stroke	70.0mm x 58.0mm
Compression Ratio	8.3:1
Starting System	Electric & pull start
Transmission	5-speed with reverse
Drive System	Shaft drive
Fuel Capacity	3.7 gallons (14 liters)
Oil Capacity	1.6 quarts (1.5 liters)
Tire Size Front/Rear	22 x 11-8 / 22 x 11-8
Dry Weight	418 lbs (190 kg)

Safety Precautions

Essential safety information for operating and servicing your Yamaha Moto 4 225.

Always wear helmet, eye protection, and protective clothing when operating.
Never operate under influence of alcohol or drugs.
Service in well-ventilated area; avoid open flames near fuel system.
Use proper tools and follow torque specifications.
Disconnect battery before electrical work.

WARNING! ATVs can be hazardous to operate. Never carry passengers. Avoid paved surfaces. Complete training course before operation.

Maintenance Schedule

Recommended maintenance intervals for optimal performance.

Pre-ride inspection: Check tires, controls, lights, oil level.
Every 100 miles: Check air filter, brake fluid, drive shaft boot.
Every 500 miles: Change engine oil and filter.
Every 1,000 miles: Check valve clearance, spark plug.
Every 2,000 miles: Change final drive oil.
Seasonal: Lubricate cables, check battery.

NOTE: More frequent maintenance required under severe conditions (dust, mud, extended operation).

Engine Service

Engine maintenance and repair procedures.

Oil Change: Warm engine, drain oil, replace filter, refill with 10W-40.
Valve Clearance: Intake: 0.004-0.006 in (0.10-0.15 mm), Exhaust: 0.006-0.008 in (0.15-0.20 mm).
Spark Plug: NGK DR8ES, gap 0.028-0.031 in (0.7-0.8 mm).
Compression Test: Should be 142-171 psi (9.8-11.8 kg/cm²).
Carburetor: Main jet #115, pilot jet #40, float level 0.63 in (16 mm).

Fuel System

Carburetor and fuel system maintenance.

Fuel tank removal: Disconnect fuel line, remove mounting bolts.
Carburetor cleaning: Remove, disassemble, clean jets with compressed air.
Float adjustment: Measure from carburetor body to float top.
Fuel filter: Replace if clogged or annually.
Fuel line inspection: Check for cracks, replace if deteriorated.

CAUTION! Gasoline is extremely flammable. Work in well-ventilated area away from sparks or flames.

Electrical System

Battery, charging system, and electrical components.

Component	Specification
Battery	12V 14Ah
Charging Output	14V 15A at 5,000 rpm
Spark Plug Gap	0.028-0.031 in (0.7-0.8 mm)
Fuse	Main: 20A, Headlight: 10A
Bulb Types	Headlight: 35/35W, Brake light: 21W

Testing: Use multimeter to check battery voltage (12.6V static), charging output (13.5-14.5V running).

Transmission & Drive

Transmission service and shaft drive maintenance.

Gear oil change: Use SAE 80W-90 gear oil, capacity 0.42 qt (0.4 L).
Shift mechanism: Check for proper engagement in all gears.
Drive shaft: Inspect boot for tears, lubricate splines.
Final drive: Check oil level, change every 2,000 miles.
Clutch adjustment: Free play 0.2-0.4 in (5-10 mm) at lever.

Brake System

Front and rear brake maintenance.

Front Brakes: Dual hydraulic disc, pad thickness minimum 0.12 in (3 mm)
Rear Brake: Mechanical drum, adjustment at lever
Brake Fluid: DOT 4, change every 2 years
Bleeding: Required when air in system or fluid change
Parking Brake: Adjust cable for proper engagement

WARNING! Test brakes after service. Never reuse brake fluid.

Suspension & Steering

Front and rear suspension components.

Front suspension: Oil capacity 6.3 oz (185 ml) per fork
Rear suspension: Check shock absorber for leaks
Steering play: Should be minimal, check bearings
Wheel bearings: Check for play, repack annually
Tire pressure: 3.6 psi (25 kPa) front and rear

Troubleshooting

Problem	Possible Cause	Solution
Engine won't start	No spark, fuel issue, compression	Check spark plug, fuel flow, compression
Poor performance	Clogged air filter, carb issues	Clean air filter, check carburetor
Electrical failure	Dead battery, faulty stator	Test battery, check charging output
Transmission issues	Low oil, worn gears	Check oil level, inspect gears
Brake problems	Worn pads, air in system	Replace pads, bleed brakes

Wiring Diagrams

Complete electrical schematics for the 1986 Yamaha Moto 4 225.

Key Components: CDI unit, stator assembly, voltage regulator, starter relay, handlebar switches.

Color Codes: R=Red, B=Black, W=White, Y=Yellow, G=Green, Br=Brown, L=Blue

Service Support: For technical assistance contact Yamaha customer service or authorized dealer.