1999 Yamaha Grizzly 600 Service Manual

The 1999 Yamaha Grizzly 600 is a four-wheel-drive all-terrain vehicle (ATV) featuring a 595cc, liquid-cooled, SOHC, four-stroke engine with electric start, Ultramatic automatic transmission with engine braking, On-Command 2WD/4WD with differential lock, independent double-wishbone front suspension, swingarm rear suspension, front and rear hydraulic disc brakes, and a towing capacity of 850 lbs. This manual provides comprehensive service, maintenance, and repair information for owners and technicians.

1. General Information & Specifications 2. Periodic Maintenance & Lubrication 3. Engine & Transmission 4. Fuel & Emission Control Systems 5. Chassis & Electrical 6. Drive System 7. Suspension, Steering & Brakes 8. Body & Frame 9. Troubleshooting 10. Wiring Diagrams 11. Appendix & Torque Specifications

General Information & Specifications

Identification numbers, general specifications, and safety information for the 1999 Yamaha Grizzly 600.

Item	Specification
Model	YFM600FW (Grizzly 600 4x4)
Engine Type	Liquid-cooled, 4-stroke, SOHC, 4-valve
Displacement	595 cm³ (36.3 cu in)
Bore x Stroke	92.0 x 89.5 mm (3.62 x 3.52 in)
Compression Ratio	9.2:1
Starting System	Electric starter
Transmission	Automatic Ultramatic (V-belt, H/L/N/R/P)
Drive System	On-Command 2WD/4WD with diff lock
Fuel Tank Capacity	16.0 L (4.23 US gal)
Dry Weight	262 kg (578 lbs)

Periodic Maintenance & Lubrication

Recommended maintenance intervals and procedures to ensure optimal performance and longevity.

Pre-ride Inspection: Check tires, brakes, lights, controls, and fluid levels.
Engine Oil: Change every 100 hours or 6 months; use Yamalube 4 (10W-30) or equivalent API SG type.
Oil Filter: Replace with every oil change.
Air Filter: Clean every 20 hours; replace if damaged.
Spark Plug: Check/adjust gap every 100 hours; replace as needed (NGK DR8EA).
Drive Belt: Inspect for wear/cracks every 200 hours.
Differential Oil: Change front/rear every 200 hours (API GL-5 Hypoid gear oil SAE 80W-90).
Brake Fluid: Check level; replace every 2 years (DOT 4).
Wheel Bearings & Pivots: Lubricate with grease every 100 hours.

WARNING! Always perform maintenance in a well-ventilated area with the engine off and cool. Use proper tools and safety equipment.

Engine & Transmission

Service procedures for the engine, cylinder head, piston, crankshaft, and Ultramatic transmission.

Cylinder Head Removal: Drain coolant, remove intake/exhaust, disconnect cables, unbolt head.
Valve Adjustment: Set clearance (cold): IN 0.10–0.15 mm (0.004–0.006 in), EX 0.15–0.20 mm (0.006–0.008 in).
Piston & Cylinder: Inspect for wear/scoring; standard bore 92.000–92.015 mm.
Crankshaft & Connecting Rod: Check runout and big-end side clearance.
Oil Pump: Inspect rotor clearance; replace if beyond service limits.
Ultramatic Transmission: Inspect drive belt, sheaves, and rollers; replace worn components.
Clutch Service: Check driven clutch spring and shoe wear.

CAUTION! Mark components during disassembly for correct reassembly. Use a torque wrench for critical fasteners.

Fuel & Emission Control Systems

Carburetor adjustment, fuel pump, and emission control system service.

Carburetor: Mikuni BSR36; pilot screw initial setting: 2-1/4 turns out.
Float Height: 13.0–15.0 mm (0.51–0.59 in).
Idle Speed: 1400 ± 100 rpm (warm).
Fuel Pump: Vacuum-operated; check for leaks and flow.
Air Injection System (AIS): Inspect reed valve and hoses.
Evaporative Emission Control (if equipped): Check charcoal canister and lines.

Chassis & Electrical

Battery, charging system, ignition, and lighting system service.

Battery: YTZ7S (12V, 6Ah). Maintain specific gravity at 1.280 at 20°C (68°F).

Charging System: Output: 14.3–14.7 V at 5000 rpm. Test stator resistance: 0.21–0.31 Ω (20°C).

Ignition System: CDI unit; primary coil resistance: 0.56–0.84 Ω; spark plug gap: 0.6–0.7 mm.

Lighting: Headlight: 12V 30/30W (halogen). Check switches and grounds for faults.

Drive System

On-Command 4WD system, front and rear differentials, and drive shaft service.

On-Command System: Test engagement in 2WD/4WD/Diff Lock modes; check vacuum lines and actuator.
Front Differential: Drain oil, inspect gears and bearings; backlash: 0.10–0.20 mm.
Rear Differential: Similar procedure; check pinion bearing preload.
Drive Shafts: Inspect CV joints and boots for damage; repack with grease if necessary.

Tip: Always engage 4WD and diff lock on loose surfaces only to avoid driveline binding.

Suspension, Steering & Brakes

Front A-arm and rear swingarm suspension, steering stem, and hydraulic disc brake service.

Front Suspension: Check ball joints, bushings, and shock absorber (preload adjustable).
Rear Suspension: Inspect swingarm pivot bearings and shock.
Steering Stem: Adjust bearing preload; lubricate with grease.
Front Brakes: Dual hydraulic disc; pad thickness min: 1.5 mm; rotor thickness min: 3.0 mm.

Rear Brake: Hydraulic disc; check pedal free play (5–10 mm).

Bleeding Brakes: Use DOT 4 fluid; avoid air ingress.

WARNING! Replace brake pads in sets. Never reuse brake fluid.

Body & Frame

Plastic body panel removal, rack installation, and frame inspection.

Unplug before cleaning. Use dry cloth only; no liquids or aerosols.

CAUTION! When removing panels, note fastener locations. Inspect frame for cracks, especially near stress points and welds.

Troubleshooting

Symptom Possible Cause Corrective Action

Engine does not start Weak battery, faulty spark, fuel issue Check battery voltage, spark plug, fuel flow, carburetor.

Engine stalls or runs poorly Dirty air filter, clogged carb jet, ignition fault Clean/replace air filter, clean carburetor, check ignition timing.

Loss of power/overheating Low coolant, slipping drive belt, restricted exhaust Check coolant level, inspect drive belt and sheaves, check exhaust for blockage.

4WD not engaging Vacuum leak, faulty actuator, switch problem Inspect vacuum lines, test actuator, check switch/connections.

Excessive vibration Unbalanced wheels, worn CV joints, engine mount loose Check tire balance, inspect CV joints and boots, tighten engine mounts.

Brakes dragging or weak Contaminated pads, air in lines, master cylinder issue Clean/replace pads, bleed brakes, rebuild master cylinder.

Wiring Diagrams

Complete electrical schematics for the 1999 Grizzly 600, including color codes and connector locations.

Note: Refer to the separate fold-out diagram sheet included with the manual for full-size, detailed wiring diagrams.

Appendix & Torque Specifications

Critical fastener torque values and general service data.

Fastener Torque

Cylinder Head Bolts 40 N·m (4.0 kgf·m, 29 ft·lb)

Spark Plug 13 N·m (1.3 kgf·m, 9.4 ft·lb)

Engine Oil Drain Plug 23 N·m (2.3 kgf·m, 17 ft·lb)

Front Wheel Axle Nut 105 N·m (10.5 kgf·m, 76 ft·lb)

Rear Wheel Axle Nut 105 N·m (10.5 kgf·m, 76 ft·lb)

Swingarm Pivot Bolt 105 N·m (10.5 kgf·m, 76 ft·lb)

Steering Stem Nut 75 N·m (7.5 kgf·m, 54 ft·lb)

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

1999 Yamaha Grizzly 600 Service Manual © - All Rights Reserved 2025

Symptom	Possible Cause	Corrective Action
Engine does not start	Weak battery, faulty spark, fuel issue	Check battery voltage, spark plug, fuel flow, carburetor.
Engine stalls or runs poorly	Dirty air filter, clogged carb jet, ignition fault	Clean/replace air filter, clean carburetor, check ignition timing.
Loss of power/overheating	Low coolant, slipping drive belt, restricted exhaust	Check coolant level, inspect drive belt and sheaves, check exhaust for blockage.
4WD not engaging	Vacuum leak, faulty actuator, switch problem	Inspect vacuum lines, test actuator, check switch/connections.
Excessive vibration	Unbalanced wheels, worn CV joints, engine mount loose	Check tire balance, inspect CV joints and boots, tighten engine mounts.
Brakes dragging or weak	Contaminated pads, air in lines, master cylinder issue	Clean/replace pads, bleed brakes, rebuild master cylinder.

Fastener	Torque
Cylinder Head Bolts	40 N·m (4.0 kgf·m, 29 ft·lb)
Spark Plug	13 N·m (1.3 kgf·m, 9.4 ft·lb)
Engine Oil Drain Plug	23 N·m (2.3 kgf·m, 17 ft·lb)
Front Wheel Axle Nut	105 N·m (10.5 kgf·m, 76 ft·lb)
Rear Wheel Axle Nut	105 N·m (10.5 kgf·m, 76 ft·lb)
Swingarm Pivot Bolt	105 N·m (10.5 kgf·m, 76 ft·lb)
Steering Stem Nut	75 N·m (7.5 kgf·m, 54 ft·lb)