Yamaha Grizzly 125 Service Manual

The Yamaha Grizzly 125 is a compact, versatile all-terrain vehicle (ATV) designed for recreational and utility use. This service manual provides comprehensive information for maintenance, troubleshooting, and repair of the Grizzly 125, including engine specifications, chassis details, electrical systems, and periodic maintenance schedules. Below are key sections covering safety, features, maintenance procedures, specifications, and troubleshooting.

1. Features at a Glance 2. Safety Precautions 3. Periodic Maintenance 4. Specifications 5. Engine Service 6. Chassis & Suspension 7. Electrical System 8. Fuel System 9. Troubleshooting 10. Warranty & Support

Features at a Glance

Key components: 4-stroke air-cooled engine, automatic transmission with reverse, independent rear suspension, front and rear hydraulic disc brakes, electric start, and durable steel frame.

Feature	Description
Engine Type	4-stroke, SOHC, air-cooled single cylinder
Displacement	124cc
Transmission	Automatic CVT with reverse
Suspension Front	Independent double wishbone
Suspension Rear	Swingarm with single shock
Brakes Front/Rear	Hydraulic disc
Starting System	Electric start with backup recoil
Fuel Capacity	Approx. 2.1 gallons (8 liters)
Load Capacity	Up to 198 lbs (90 kg)
Tires	ATV-specific knobby tires

Safety Precautions

Always follow safety guidelines when servicing the ATV.

Work in a well-ventilated area away from sparks or flames.
Use proper tools and protective equipment (gloves, goggles).
Disconnect battery before electrical work.
Support ATV securely on a stand when lifting.
Allow engine to cool before servicing.

WARNING! Gasoline is flammable; handle with care. Always refer to the owner's manual for operational safety.

Periodic Maintenance

Regular maintenance ensures optimal performance and longevity.

Engine oil: Check level before each ride; change every 100 hours or 6 months.
Air filter: Clean every 50 hours; replace if damaged.
Spark plug: Inspect and clean every 100 hours; replace as needed.
Brake fluid: Check level monthly; replace every 2 years.
Tire pressure: Check before each ride (recommended: 3.5 psi front, 4.0 psi rear).
Drive chain: Lubricate every 20 hours; adjust tension as specified.

CAUTION! Use only Yamaha-recommended fluids and parts. Tighten fasteners to specified torque.

Specifications

Engine: 124cc, 4-stroke, air-cooled, SOHC.
Bore x Stroke: 54.0 mm x 54.0 mm.
Compression Ratio: 9.5:1.
Fuel System: Carburetor with choke.
Ignition System: CDI.
Transmission: Automatic CVT with high/low range and reverse.
Final Drive: Shaft drive.
Suspension Travel Front/Rear: 4.3 in / 5.1 in.
Brakes: Hydraulic disc front and rear.
Dimensions (LxWxH): 68.9 in x 41.3 in x 41.7 in.
Dry Weight: Approx. 386 lbs (175 kg).

Engine Service

Procedures for engine maintenance and repair.

Valve Clearance Adjustment: Check every 200 hours. Intake: 0.10–0.15 mm, Exhaust: 0.15–0.20 mm.

Oil Change: Use SAE 10W-30, API SG or higher. Capacity: 1.1 qt (1.0 L) with filter change.

Cooling System: Air-cooled; ensure fins are clean and unobstructed.

Compression Test: Normal range: 142–199 psi. Low compression indicates worn rings or valves.

Chassis & Suspension

Inspection and service of frame, suspension, and brakes.

Check frame for cracks or damage after heavy use.
Inspect suspension components for wear; lubricate pivot points.
Brake pads: Replace if thickness is less than 0.12 in (3 mm).
Wheel bearings: Check for play; repack with grease annually.

Tip: Torque axle nuts to 65 ft-lb (88 Nm).

Electrical System

Battery, charging system, and lighting.

Battery: 12V, 10Ah. Keep terminals clean; check voltage (12.6V fully charged).
Charging system: Output approx. 14V at 3000 rpm.
Headlight/Taillight: Check bulbs for operation; replace if burnt out.
Fuses: Main fuse 30A; spare fuses in fuse box.

WARNING! Disconnect negative terminal first when removing battery.

Fuel System

Carburetor service and fuel delivery.

Fuel filter: Replace annually or if clogged.
Carburetor adjustment: Idle speed 1400 ± 100 rpm.
Throttle cable: Check for smooth operation; adjust free play to 0.2–0.4 in.
Fuel tank: Inspect for leaks; clean sediment periodically.

CAUTION! Use fresh unleaded gasoline (87 octane minimum).

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Dead battery, clogged fuel filter, faulty spark plug	Charge/replace battery; clean fuel filter; check/replace spark plug.
Poor performance	Dirty air filter, incorrect valve clearance, worn drive belt	Clean/replace air filter; adjust valves; inspect CVT belt.
Overheating	Low oil, clogged cooling fins, rich/lean fuel mixture	Check oil level; clean fins; adjust carburetor.
Brakes dragging	Contaminated pads, stuck caliper piston	Clean or replace pads; rebuild caliper if necessary.
Electrical failure	Blown fuse, loose connection, bad stator	Check fuses and wiring; test stator output.

Reset ECU: Disconnect battery for 10 minutes to clear fault codes.

Service: Contact authorized Yamaha dealer or visit www.yamahamotorsports.com.