Yamaha Grizzly 550 Service Manual

The Yamaha Grizzly 550 is a rugged, all-terrain vehicle (ATV) designed for work and recreation. This service manual provides comprehensive information for maintenance, troubleshooting, and repair of the Grizzly 550, including engine specifications, chassis details, electrical systems, periodic maintenance schedules, and disassembly/assembly procedures. Below are key sections covering safety, specifications, maintenance, troubleshooting, and component service.

1. General Information & Safety 2. Specifications 3. Periodic Maintenance 4. Engine Service 5. Chassis & Drive System 6. Electrical System 7. Troubleshooting 8. Disassembly & Assembly 9. Lubrication Points 10. Storage & Winterization 11. Warranty & Support

General Information & Safety

This manual is intended for qualified service technicians. Always follow safety precautions to prevent injury or damage.

Safety Item	Description
Work Area	Work in a well-ventilated, clean area free of sparks or flames.
Personal Protective Equipment	Wear safety glasses, gloves, and appropriate clothing.
Lifting & Support	Use proper ATV stands; never work under unsupported vehicle.
Battery Safety	Disconnect negative terminal first; avoid sparks near battery.
Fuel System	Drain fuel before service; no smoking or open flames.
Hot Components	Allow engine and exhaust to cool before servicing.
Torque Specifications	Always use a torque wrench for critical fasteners.
Test Riding	After service, test in a safe, open area.

Specifications

Model: Yamaha Grizzly 550 (YFM55F).
Engine Type: 4-stroke, SOHC, liquid-cooled, single cylinder.
Displacement: 558 cc.
Bore x Stroke: 92.0 mm x 84.0 mm.
Compression Ratio: 9.5:1.
Fuel System: Mikuni BSR42 carburetor.
Starting System: Electric start with auxiliary pull start.
Transmission: Automatic Ultramatic V-belt with all-wheel drive (2WD/4WD selectable).
Front/Rear Suspension: Independent double wishbone with 7.1 in travel / Swingarm with 9.5 in travel.
Front/Rear Brakes: Dual hydraulic disc / Hydraulic disc.
Tires: AT25 x 8-12 front, AT25 x 10-12 rear.
Fuel Capacity: 4.8 gallons (18.2 L).
Dry Weight: 600 lb (272 kg).

Periodic Maintenance

Follow the maintenance schedule to ensure optimal performance and longevity.

Pre-Ride Inspection: Check tires, brakes, lights, controls, and fluid levels.
After First 20 Hours / 100 Miles: Change engine oil and filter. Check all fasteners.
Every 100 Hours / 600 Miles: Change engine oil and filter. Clean air filter. Inspect drive belt, brake pads, and suspension.
Every 200 Hours / 1200 Miles: Change differential gear oil (front and rear). Check valve clearance. Inspect spark plug.
Every Year: Change brake fluid. Inspect and lubricate all cables, pivots, and bearings.

WARNING! Failure to perform periodic maintenance can lead to premature wear, failure, or unsafe operation.

Engine Service

Procedures for engine maintenance and repair.

Oil Change: Use SAE 10W-30 or 10W-40 4-stroke motorcycle oil meeting API SG or higher. Capacity: 2.6 qt (2.5 L) with filter change.

Valve Clearance Adjustment: Intake: 0.10–0.15 mm (0.004–0.006 in). Exhaust: 0.15–0.20 mm (0.006–0.008 in). Check with engine cold.

Carburetor Adjustment: Pilot screw initial setting: 2-1/4 turns out from lightly seated. Idle speed: 1400 ± 100 rpm.

Cooling System: Use a 50/50 mix of ethylene glycol antifreeze and distilled water. Capacity: 1.6 qt (1.5 L).

Chassis & Drive System

Service information for the frame, suspension, brakes, and drivetrain.

Front/Rear Differential Oil: Use SAE 80W-90 API GL-5 gear oil. Capacity: Front 0.26 qt (0.25 L), Rear 0.53 qt (0.50 L).
Drive Belt Inspection: Check for cracks, fraying, or excessive wear. Belt width wear limit: 28.0 mm (1.10 in).
Brake Pad Wear Limit: Minimum thickness 1.0 mm (0.04 in).
Wheel Bearing Inspection: Check for play or roughness. Lubricate with lithium-based grease.
Front Toe-in Adjustment: 0–10 mm (0–0.4 in).

Tip: Always clean the area around fill plugs before removing to prevent contamination.

Electrical System

Battery, charging system, lighting, and starting circuit details.

Component	Specification
Battery	12V, 12Ah (YTZ12S).
Charging System	Three-phase AC magneto with voltage regulator.
Spark Plug	NGK DR8EA or DENSO X24EPR-U9. Gap: 0.7–0.8 mm (0.028–0.031 in).
Headlight	12V, 30/30W (halogen).
Fuse	Main: 30A. Sub fuses: 10A, 15A.

CAUTION! Disconnect battery before performing electrical work to prevent shorts.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine does not start	Weak battery, faulty spark plug, clogged fuel system	Check battery voltage; inspect spark plug; clean carburetor and fuel filter.
Poor engine performance	Dirty air filter, incorrect valve clearance, worn drive belt	Clean/replace air filter; adjust valves; inspect drive belt.
Overheating	Low coolant, clogged radiator, faulty thermostat	Check coolant level; clean radiator fins; test thermostat.
Excessive vibration	Unbalanced wheels, loose engine mounts, worn U-joints	Check wheel balance; tighten mounts; inspect drive shaft joints.
Electrical failure	Blown fuse, poor ground, faulty switch	Check all fuses; clean battery terminals and grounds; test switches.
Brakes dragging or weak	Contaminated fluid, air in lines, worn pads	Flush brake fluid; bleed system; replace pads.

Disassembly & Assembly

General procedures for major component removal.

Body Panels: Remove seat, then plastic panels using appropriate sockets and trim tools.
Fuel Tank: Disconnect fuel line and vent hose, then remove mounting bolts.
Carburetor: Disconnect throttle and choke cables, fuel line, and vent hose before removal.
Drive Belt: Remove left side cover, clutch cover, and variator to access belt.
Front/Rear Suspension: Support ATV properly before removing A-arms or swingarm.

WARNING! Take photos and label parts during disassembly to aid reassembly.

Lubrication Points

Lubricate the following points with the specified lubricant at the intervals noted.

Throttle Cable: Lightweight cable lubricant - Every 100 hours.
Choke Cable: Lightweight cable lubricant - Every 100 hours.
Brake & Clutch Levers: Multi-purpose grease - Every 100 hours.
Swingarm Pivot: Lithium-based grease - Every 200 hours.
Steering Stem Bearings: Lithium-based grease - Every 200 hours.
Drive Shaft Splines: Molybdenum disulfide grease - Every 200 hours.

Storage & Winterization

Proper procedures for storing the ATV for extended periods.

Change engine oil and filter.
Fill fuel tank and add fuel stabilizer. Run engine for 5 minutes.
Remove spark plug, add a teaspoon of oil into cylinder, and crank engine slowly. Reinstall plug.
Clean entire ATV thoroughly. Apply protectant to plastic and rubber.
Inflate tires to recommended pressure and place ATV on stands to relieve tire stress.
Disconnect battery negative terminal and store battery in a cool, dry place on a maintainer.
Cover ATV with a breathable cover.

CAUTION! Storing with old fuel can cause carburetor varnishing and starting issues.

Warranty & Support

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

For technical support, genuine Yamaha parts, and additional service information:

Contact an authorized Yamaha ATV dealer.
Visit the Yamaha Motors website: www.yamahamotorsports.com.
Yamaha Customer Relations: 1-800-962-7926.

This manual is a supplement to the official Yamaha Service Manual. Specifications and procedures are subject to change.