1998 Yamaha Grizzly 600 Service Manual

The 1998 Yamaha Grizzly 600 is a 4x4 all-terrain vehicle (ATV) featuring a 595cc, 4-stroke, SOHC, liquid-cooled engine with electric start, Ultramatic automatic transmission with engine braking, On-Command 2WD/4WD with differential lock, independent double-wishbone front suspension, and a swingarm rear suspension. This manual provides comprehensive service, maintenance, and repair information for owners and technicians. Below are key sections covering specifications, periodic maintenance, engine service, transmission, electrical system, troubleshooting, and more.

1. General Information & Specifications 2. Periodic Maintenance & Lubrication 3. Engine Service 4. Fuel System & Carburetor 5. Ultramatic Transmission & Drive Train 6. Chassis & Suspension 7. Electrical System 8. Brake System 9. Troubleshooting 10. Wiring Diagrams 11. Appendix & Torque Specifications

General Information & Specifications

Key identification: Model code YFM600FA, VIN location on frame. Overall dimensions, weight, and capacities.

Item	Specification
Model	Yamaha Grizzly 600 (YFM600FA)
Engine type	4-stroke, SOHC, liquid-cooled, single cylinder
Displacement	595 cc
Bore x Stroke	92.0 mm x 89.5 mm
Compression ratio	8.5:1
Starting system	Electric starter (primary), recoil starter (backup)
Transmission	Ultramatic automatic V-belt with H, L, N, R ranges
Drive system	On-Command 2WD/4WD with differential lock
Fuel tank capacity	15.1 liters (4.0 US gal)
Oil capacity	2.5 liters (2.6 US qt) with filter change

Periodic Maintenance & Lubrication

Follow the maintenance schedule for optimal performance and longevity. Use recommended Yamaha lubricants and parts.

Pre-ride inspection: Check tires, brakes, lights, controls, and fluid levels.
Engine oil: Change every 100 hours or 6 months; replace filter every other change.
Air filter: Clean every 20-40 hours; replace if damaged.
Drive chain: Adjust slack to 40-50 mm; lubricate regularly.
Front & rear gearcase oil: Check level; change annually.
Brake fluid: Inspect level; replace every 2 years.
Spark plug: Clean and gap every 100 hours; replace as needed.

WARNING! Always stop engine and allow to cool before servicing. Use proper tools and safety equipment.

Engine Service

Detailed procedures for cylinder head, valve train, piston, crankshaft, and lubrication system.

Removal: Disconnect battery, drain coolant, remove engine mounting bolts.
Cylinder head: Check for warpage; service valves (intake 0.10-0.15 mm, exhaust 0.15-0.20 mm).
Piston & rings: Inspect for wear; measure cylinder bore (standard 92.000-92.015 mm).
Crankshaft & bearings: Check runout (limit 0.03 mm); replace if out of spec.
Oil pump: Inspect rotor clearance; prime before installation.
Reassembly: Use new gaskets; torque head bolts in sequence (55 Nm).

CAUTION! Mark all parts during disassembly. Follow torque specifications precisely.

Fuel System & Carburetor

Carburetor: Mikuni BSR36; pilot screw initial setting 2 turns out.
Float height: 13.0 mm.
Idle speed: 1400 ± 100 rpm (warm).
Fuel valve: Vacuum operated; inspect diaphragm.
Fuel pump: Check pressure and flow.
Throttle cable: Adjust free play (3-5 mm).
Choke: Ensure smooth operation.

Ultramatic Transmission & Drive Train

Service for V-belt, driven clutch, drive clutch, and On-Command system.

V-belt: Inspect for wear/cracks; width limit 27.9 mm. Clutch sheaves: Clean and inspect for scoring. Drive chain: Adjust tension. On-Command: Test 2WD/4WD/diff lock operation; check vacuum lines and actuator. Gearcase: Drain and refill with SAE 80W-90 gear oil (0.25 L each).

Chassis & Suspension

Front: Independent double-wishbone with 5-way preload adjustable shocks. Rear: Swingarm with 5-way preload adjustable shock.

Wheel removal: Loosen axle nut, lift ATV, remove wheel.
Front A-arms: Check bushings and ball joints for play.
Shock absorbers: Inspect for leaks; adjust preload as needed.
Steering: Check for looseness; adjust if necessary.
Tires: Pressure 20 kPa (0.20 kgf/cm², 2.9 psi) front and rear.

Tip: Always support ATV securely on stands before working underneath.

Electrical System

Battery: 12V, 19Ah. Charging system: AC magneto with rectifier/regulator.

Battery: Check specific gravity (1.280 at 20°C); keep terminals clean.
Starter: Test draw (max 180A); inspect brushes.
Lighting: Check all bulbs and connections.
Ignition: Check coil resistance (primary 0.56-0.84 Ω, secondary 6.65-9.95 kΩ).
Switches: Test handlebar controls for continuity.
Fuses: Main 30A, headlight 10A, signal 10A.

WARNING! Disconnect battery negative terminal first when working on electrical system.

Brake System

Front: Dual hydraulic disc. Rear: Hydraulic disc with parking brake.

Brake pads: Replace if thickness less than 1.0 mm. Discs: Check for warpage (limit 0.15 mm). Fluid: Use DOT 4. Bleeding: Follow procedure to remove air. Parking brake: Adjust cable tension.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine does not start	Fuel, spark, compression	Check fuel flow, spark plug, compression (standard 9.5 kg/cm²).
Poor performance/loss of power	Clogged air filter, carburetor, exhaust	Clean air filter, carburetor jets, check exhaust restriction.
Transmission slipping/no drive	Worn V-belt, clutch issue	Inspect V-belt width; clean clutch sheaves.
4WD not engaging	Vacuum leak, actuator fault	Check vacuum lines and On-Command actuator.
Electrical failure	Blown fuse, bad battery, faulty stator	Check fuses, battery voltage, stator output (AC).
Overheating	Low coolant, clogged radiator	Check coolant level and radiator for debris.

Reset: For ECU/electronic issues, disconnect battery for 10 minutes.

Wiring Diagrams

Complete color-coded wiring diagrams for the entire ATV, including main harness, lighting, ignition, and charging systems. Use for diagnosing electrical faults.

Appendix & Torque Specifications

Critical torque values for safe reassembly. Use a calibrated torque wrench.

Fastener	Torque
Cylinder head bolts	55 Nm (40 lbf·ft)
Spark plug	12.5 Nm (9.0 lbf·ft)
Engine mounting bolts	60 Nm (43 lbf·ft)
Front axle nut	105 Nm (76 lbf·ft)
Rear axle nut	105 Nm (76 lbf·ft)
Wheel nuts	55 Nm (40 lbf·ft)
Oil drain plug	23 Nm (17 lbf·ft)

Service: For genuine Yamaha parts and technical support, contact an authorized Yamaha dealer or visit www.yamaha-motor.com.