Yamaha 660 Grizzly Manual

The Yamaha 660 Grizzly is a high-performance 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 safety, operation, maintenance, specifications, and troubleshooting for the Grizzly 660 model.

Features at a Glance

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

Feature	Description
Engine	660cc liquid-cooled, 4-stroke, SOHC, 4-valve
Transmission	Ultramatic automatic with engine braking
Drive System	On-Command 2WD/4WD with differential lock
Suspension Front	Independent double wishbone
Suspension Rear	Swingarm with adjustable preload
Brakes	Dual hydraulic disc front, sealed wet multi-disc rear
Instrumentation	Digital display with speedometer, odometer, trip meter, gear indicator, fuel gauge
Fuel Capacity	5.3 gallons (20 liters)
Towing Capacity	Up to 1,212 lbs (550 kg)
Rack Capacity	Front 88 lbs (40 kg), Rear 176 lbs (80 kg)

Pre-Ride Inspection

Before each ride, perform a thorough 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 for proper function and check fluid levels.
4. Check all lights (headlight, taillight, brake light) and indicators.
5. Verify throttle moves smoothly and returns automatically.
6. Check drive chain tension and lubrication (if applicable).
7. Ensure all nuts and bolts are tight, especially on critical components.

WARNING! Never operate the ATV if any inspection item fails. Address issues before riding.

Controls and Indicators

Familiarize yourself with all controls before operation.

Left Handlebar: Headlight dimmer switch, turn signal switch, horn button, 2WD/4WD selector, differential lock switch.

Right Handlebar: Electric start button, engine stop switch, throttle lever, front brake lever.

Instrument Panel: Speedometer, odometer, trip meter, fuel gauge, gear position indicator, 4WD indicator, differential lock indicator, neutral indicator, high beam indicator.

Foot Controls: Rear brake pedal, shift lever (for forward, neutral, reverse).

Key Switch: OFF, ON, START positions.

Specifications

• Engine Type: 660cc liquid-cooled, 4-stroke, SOHC, 4-valve.
• Bore x Stroke: 102.0 mm x 80.5 mm.
• Compression Ratio: 9.5:1.
• Fuel System: Mikuni BSR42 carburetor.
• Ignition System: DC-CDI.
• Starting System: Electric starter.
• Transmission: Ultramatic automatic V-belt with all-wheel engine braking.
• Drive System: Yamaha On-Command 2WD/4WD with differential lock.
• Suspension Front: Independent double wishbone, 7.1 in travel.
• Suspension Rear: Swingarm, 9.5 in travel, adjustable preload.
• Brakes Front: Dual hydraulic disc.
• Brakes Rear: Sealed wet multi-disc.
• Tires Front/Rear: AT25 x 8-12 / AT25 x 10-12.
• Dimensions (LxWxH): 83.1 in x 46.5 in x 49.6 in.
• Ground Clearance: 11.0 in.
• Dry Weight: 600 lbs.

Operation Procedures

Starting, riding, and stopping your Grizzly 660.

1. Starting: Ensure transmission is in Neutral. Turn key ON. Pull brake lever. Press start button.
2. Driving: Select Forward (F) or Reverse (R) with shift lever. Apply throttle gradually.
3. 4WD Operation: Use On-Command switch to select 2WD or 4WD. Engage differential lock only at low speeds when extra traction is needed.
4. Stopping: Release throttle, apply brakes evenly. Shift to Neutral when stopped.
5. Engine Break-In: Vary speed for first 10 hours. Avoid full throttle starts and prolonged constant speed.

CAUTION! Always wear appropriate safety gear. Never operate on public roads unless legally permitted.

Maintenance Schedule

Regular maintenance ensures longevity and reliability. Refer to the manual for detailed procedures.

Item	Every 20 hrs / 300 mi	Every 100 hrs / 1500 mi	Every 200 hrs / 3000 mi
Engine Oil	Check Level	Change	-
Oil Filter	-	Replace	-
Air Filter	Clean/Inspect	Replace if needed	-
Spark Plug	Inspect	Clean/Adjust Gap	Replace
Drive Belt	Inspect	-	Replace
Brake Fluid	Inspect Level	-	Change
Wheel Nuts/Bolts	Check Tightness	-	-
Steering System	Check for play	Lubricate	-

Basic Troubleshooting

Common issues and initial checks.

1. Engine won't start: Check fuel, battery charge, kill switch position, neutral indicator, spark plug.
2. Poor performance/loss of power: Check air filter, fuel filter, spark plug, carburetor settings.
3. Overheating: Check coolant level, radiator for debris, thermostat operation.
4. Electrical issues: Check fuses, battery connections, ground wires.
5. Abnormal noise/vibration: Inspect drive belt, wheel bearings, skid plate, exhaust system.

Storage Guidelines

Proper storage prevents damage during periods of non-use.

1. Clean the ATV thoroughly.
2. Change engine oil and filter.
3. Fill fuel tank and add fuel stabilizer. 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; store battery in a cool, dry place on a maintainer.
6. Inflate tires to recommended pressure and store on blocks to lift tires off ground.
7. Cover with a breathable fabric cover.

CAUTION! Store in a cool, dry place away from direct sunlight and sources of ignition.

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 on a single-rider ATV.
• Never operate on paved surfaces or public roads (unless designated).
• Never operate under the influence of alcohol or drugs.
• Ride only on designated trails at safe speeds appropriate for conditions.
• Take a training course. Supervise riders under 16; ATVs are not toys.
• Inspect your ATV before each use.

WARNING! Failure to follow instructions can result in serious injury or death.

Warranty & Support

Yamaha Motor Corporation, U.S.A. provides a limited warranty. See your dealer for details. For technical support, parts, or service manuals, contact an authorized Yamaha ATV dealer or visit the Yamaha Motors website.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine cranks but won't start	No fuel, bad spark, flooded	Check fuel valve, spark plug condition and gap, use choke properly.
Loss of power uphill	Clutch slipping, dirty air filter	Inspect drive belt and clutch sheaves; clean or replace air filter.
Hard steering	Low tire pressure, damaged components	Inflate tires to spec; inspect tie rods, ball joints, steering stem bearings.
Brakes feel spongy	Air in lines, low fluid, worn pads	Bleed brake system; check fluid level and pad thickness.
Battery drains quickly	Parasitic draw, bad battery, faulty stator	Check for accessory draws; load test battery; test stator output.
Overheating	Low coolant, clogged radiator, bad thermostat	Check coolant level; clean radiator fins; test/replace thermostat.
4WD not engaging	Switch failure, actuator issue, fuse	Check switch operation, actuator motor, and related fuses.

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

Service: Contact your authorized Yamaha ATV dealer.