Yamaha Grizzly 660 Manual

The Yamaha Grizzly 660 is a powerful all-terrain vehicle (ATV) featuring a 660cc liquid-cooled, 4-stroke, SOHC engine, Ultramatic automatic transmission with engine braking, On-Command 2WD/4WD with differential lock, independent double wishbone front suspension, and a robust chassis. This manual covers essential information for safe operation, maintenance, specifications, troubleshooting, and regulatory compliance.

Features at a Glance

Key components: 660cc engine, Ultramatic transmission, On-Command 4WD system, front and rear racks, digital instrument panel, and tow hitch.

Feature	Description
Engine	660cc liquid-cooled, 4-stroke, SOHC
Transmission	Ultramatic automatic with engine braking
Drive System	On-Command 2WD/4WD with diff lock
Suspension	Independent double wishbone front, swingarm rear
Brakes	Dual hydraulic disc front, sealed wet brake rear
Fuel Capacity	4.8 gallons (18.2 liters)
Towing Capacity	Up to 1102 lbs (500 kg)
Instrumentation	Digital display with speedometer, odometer, trip meter, fuel gauge, gear indicator
Lighting	Halogen headlights, LED tail/brake lights
Storage	Front and rear cargo racks

Pre-Ride Inspection

Always perform a pre-ride inspection to ensure safe operation.

1. Check fuel level and ensure there are no leaks.
2. Inspect tires for proper pressure and any damage.
3. Test brakes (front and rear) for proper function.
4. Check all lights (headlights, brake lights, indicators).
5. Verify throttle moves smoothly and returns automatically.
6. Check oil level and coolant level (if applicable).
7. Ensure all controls (steering, levers) operate freely.

WARNING! Never operate the ATV if any issues are found during inspection. Address problems before riding.

Controls and Indicators

Familiarize yourself with all controls before riding.

Handlebar Controls: Throttle lever, brake levers (front/rear), On-Command 2WD/4WD switch, differential lock switch, ignition switch, light switch, start button, engine stop switch.

Instrument Panel: Speedometer, odometer, trip meter, fuel gauge, gear position indicator, 4WD indicator, differential lock indicator, neutral indicator, high-temperature warning light, oil pressure warning light.

Other Controls: Parking brake lever, fuel valve, choke knob (on carbureted models), shift lever (for models with selectable gears).

Specifications

• Engine Type: 660cc, liquid-cooled, 4-stroke, SOHC, 4-valve
• Bore x Stroke: 102.0 mm x 80.5 mm
• Compression Ratio: 9.2:1
• Fuel System: Mikuni BSR40 carburetor (or fuel injection on later models)
• Starting System: Electric start with auxiliary recoil
• Transmission: Yamaha Ultramatic automatic V-belt with all-wheel engine braking
• Drive Train: Shaft drive
• Suspension Front: Independent double wishbone, 7.1 in travel
• Suspension Rear: Swingarm, 9.5 in travel
• Brakes Front: Dual hydraulic disc
• Brakes Rear: Sealed wet multi-disc brake
• Tires Front: AT25 x 8-12
• Tires Rear: AT25 x 10-12
• Dimensions (LxWxH): 83.1 in x 46.5 in x 49.2 in
• Dry Weight: 617 lbs (280 kg)

Operation Guidelines

Always wear appropriate safety gear and follow safe riding practices.

1. Start the engine: Ensure transmission is in neutral, apply parking brake, turn ignition ON, pull choke (if cold), press start button.
2. Select drive mode: Use On-Command switch for 2WD or 4WD. Engage diff lock only when needed for extreme traction.
3. Riding: Release parking brake, apply throttle smoothly. Use both brakes for controlled stopping.
4. On-Command System: 2WD for normal conditions; 4WD for loose, slippery, or steep terrain.
5. Avoid sudden throttle or brake inputs, especially on loose surfaces.

CAUTION! Never operate on public roads unless legally permitted. Always be aware of your surroundings and terrain limitations.

Maintenance Schedule

Regular maintenance is crucial for longevity and safety. Refer to the detailed service manual for complete procedures.

Item	Every 20 hrs / 100 mi	Every 100 hrs / 500 mi	Every 200 hrs / 1000 mi
Engine Oil	Check level	Change	-
Oil Filter	-	Replace	-
Air Filter	Inspect/Clean	-	Replace
Spark Plug	Inspect	-	Replace
Brake Pads	Inspect	-	Replace as needed
Drive Shaft Boots	Inspect	-	-
Nuts & Bolts	Tighten	-	-
Wheel Bearings	-	Inspect/Grease	-

Always use genuine Yamaha parts and recommended lubricants.

Basic Troubleshooting

If your Grizzly 660 experiences issues, check these common points before seeking service.

1. Engine won't start: Check battery charge, fuel level, fuel valve position, kill switch position, and spark plug connection.
2. Poor performance/loss of power: Check air filter for clogging, fuel quality, and spark plug condition.
3. Overheating: Check coolant level, radiator for debris blockage, and ensure fan is operating.
4. Brakes feel spongy or weak: Check brake fluid level and inspect for leaks. May need bleeding.
5. Unusual noises: Identify source. Check for loose components, worn bearings, or drive belt issues.

Storage Procedures

Proper storage prevents damage during periods of non-use.

1. Clean the ATV thoroughly.
2. Change engine oil and filter.
3. Add fuel stabilizer to a full tank of fuel and run engine for 5 minutes.
4. Remove spark plug, add a teaspoon of oil into cylinder, crank engine slowly, reinstall plug.
5. Disconnect battery negative terminal and store battery in a cool, dry place on a maintainer.
6. Inflate tires to recommended pressure and block the ATV off the ground.
7. Store in a cool, dry place, covered with a breathable cover.

Safety Information

ATVs can be hazardous to operate. Always follow these rules:

• Always wear a helmet, eye protection, gloves, long sleeves, long pants, and over-the-ankle boots.
• Never carry passengers unless the ATV is specifically designed for more than one person.
• Never operate on paved surfaces or public roads (except to cross when legal and safe).
• Never operate under the influence of alcohol or drugs.
• Ride only on designated trails and areas where ATV use is permitted.
• Use extra caution on difficult terrain. The Grizzly 660 is not a toy and requires skill to operate safely.
• Supervise riders under 16 years of age. Complete a training course.

WARNING! FAILURE TO FOLLOW INSTRUCTIONS COULD RESULT IN SERIOUS INJURY OR DEATH.

Warranty & Support

Yamaha Motor Corporation, U.S.A. provides a limited warranty. Refer to your warranty booklet for specific terms and duration.

For technical support, service locations, or to order parts:

• Visit: www.yamahamotorsports.com
• Contact your local authorized Yamaha ATV dealer.
• Yamaha Customer Relations: 1-800-962-7926

Always provide your model name (Grizzly 660) and Vehicle Identification Number (VIN) when seeking support.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine cranks but won't start	No fuel, bad spark, flooded engine	Check fuel valve, spark plug, try starting with throttle wide open.
Loss of power, engine bogs	Clogged air filter, dirty carburetor, worn drive belt	Clean/replace air filter, service carburetor, inspect drive belt.
ATV pulls to one side	Uneven tire pressure, misalignment, brake drag	Check and adjust tire pressures, inspect suspension and brakes.
Unusual vibration	Loose wheel, damaged tire, unbalanced drive shaft	Tighten lug nuts, inspect tires and rims, check U-joints.
4WD not engaging	Faulty switch, actuator, or wiring	Check switch operation, listen for actuator click, inspect wiring harness.
Battery drains quickly	Faulty regulator/rectifier, parasitic draw	Test charging system, check for accessories causing draw.
Overheating	Low coolant, clogged radiator, faulty thermostat	Check coolant level and condition, clean radiator fins, test thermostat.

Note: For complex repairs, consult a qualified Yamaha technician.

Service: 1-800-962-7926; www.yamahamotorsports.com