2007 Yamaha Grizzly 350 Service Manual

The 2007 Yamaha Grizzly 350 is a rugged, all-terrain vehicle (ATV) powered by a 348cc, 4-stroke, air-cooled, SOHC engine with electric start. It features Yamaha's Ultramatic automatic transmission with engine braking, On-Command 2WD/4WD with differential lock, independent double-wishbone front suspension, and a fully sealed wet brake system. This manual provides comprehensive service, maintenance, and repair information for owners and technicians.

1. General Information 2. Specifications 3. Periodic Maintenance 4. Engine 5. Fuel System 6. Chassis 7. Electrical System 8. Troubleshooting 9. Wiring Diagrams 10. Storage & Transport 11. Safety & Warnings

General Information

This section covers vehicle identification, model features, general safety precautions, and tool requirements for servicing the Grizzly 350.

Item	Description
Model	YFM35FGA (2007 Yamaha Grizzly 350 4x4)
Identification No.	Located on the frame steering head
Key Features	Ultramatic transmission, On-Command 4WD, Electric start
Recommended Tools	Standard metric tool set, Yamaha special tools as noted
Manual Organization	Follows standard Yamaha service manual format

Specifications

Engine Type: 4-stroke, SOHC, air-cooled, single cylinder.
Displacement: 348 cm³.
Bore x Stroke: 83.0 mm x 64.5 mm.
Compression Ratio: 8.5:1.
Starting System: Electric starter with auxiliary recoil.
Transmission: Yamaha Ultramatic automatic V-belt with all-wheel engine braking.
Drive System: Yamaha On-Command 2WD/4WD with differential lock.
Suspension Front/Rear: Independent double wishbone / Swingarm.
Brakes Front/Rear: Dual hydraulic disc / Sealed wet multi-disc brake.
Tires: AT25 x 8-12 front, AT25 x 10-12 rear.
Fuel Capacity: 15.5 liters (4.1 US gal).
Oil Capacity: 2.5 liters (2.6 US qt) with filter change.

Periodic Maintenance

Follow the maintenance schedule to ensure optimal performance and longevity.

Pre-ride Inspection: Check tires, brakes, lights, controls, and fluid levels.
Every 1000 km / 600 mi or 6 months: Change engine oil and filter. Check/adjust drive chain slack (if applicable). Inspect brake pads/discs.
Every 2000 km / 1200 mi or 12 months: Clean air filter element. Check valve clearance. Inspect spark plug.
Every 2 years: Replace brake fluid. Change front and rear differential oil (4x4 models).
Lubrication Points: Grease steering stem bearings, swingarm pivot, and suspension linkages periodically.

WARNING! Always perform maintenance in a well-ventilated area with the engine off and cool. Use proper jack stands; the ATV is heavy and unstable on a single lift point.

Engine

Detailed procedures for engine removal, disassembly, inspection, and reassembly.

Cylinder Head & Valves: Removal, valve clearance adjustment (IN: 0.10–0.15 mm, EX: 0.15–0.20 mm), decarbonizing.

Cylinder & Piston: Inspection for wear, scoring, or out-of-round. Piston ring end gap and side clearance specifications.

Crankcase & Crankshaft: Splitting the crankcase, connecting rod big-end side clearance, crankshaft runout check.

Lubrication System: Oil pump inspection, oil pressure check, oil cooler cleaning.

Cooling System: (Air-cooled) Fin inspection and cleaning, cooling fan operation check.

Fuel System

Servicing the carburetor, fuel tank, and related components.

Carburetor (Mikuni BSR33): Disassembly, cleaning of jets and passages, float height adjustment (14.0 mm), pilot screw setting (initial: 2-1/4 turns out).
Fuel Tank: Removal, cleaning, and inspection for leaks.
Fuel Pump: Testing operation and flow rate.
Throttle Cable: Adjustment for proper free play (3-5 mm).

CAUTION! Gasoline is extremely flammable. Work in a well-ventilated area away from sparks or open flames.

Chassis

Frame, suspension, steering, and brake system service.

Component	Service Procedure
Front Suspension	Inspect A-arms, bushings, and shocks. Check for oil leaks on shocks.
Rear Suspension	Inspect swingarm pivot bearings and rear shock.
Steering	Check steering stem bearing adjustment and lubricate.
Front Brakes	Pad replacement, disc inspection, brake fluid change, bleeding.
Rear Brake	Adjustment of brake lever free play. Inspection of sealed wet brake unit.
Wheels & Tires	Wheel bearing inspection, tire removal/installation, pressure check.
Drive Shaft (4x4)	Inspect boots for tears and grease joints.

Electrical System

Battery, charging system, starting system, and lighting.

Battery: Type YTZ7S (12V, 6Ah). Maintenance, charging, and specific gravity check.
Charging System: Output test (at 5000 rpm: 14V DC ± 0.5V). Stator coil resistance check.
Starting System: Starter motor removal and brush inspection. Starter relay click test.
Ignition System: Spark plug gap (0.6–0.7 mm). Ignition coil resistance check.
Lighting & Switches: Headlight, taillight, brake light bulb replacement. Handlebar switch continuity checks.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine does not start	Weak battery, faulty spark plug, clogged fuel system	Check battery voltage, inspect spark, clean carburetor jets.
Poor engine performance	Dirty air filter, incorrect valve clearance, restricted exhaust	Clean/replace air filter, adjust valves, check exhaust for blockage.
Transmission slippage	Worn drive belt, dirty clutch sheaves	Inspect drive belt for wear/cracks, clean primary/secondary clutch.
4WD not engaging	Faulty actuator, wiring issue, vacuum lines (if applicable)	Check On-Command switch operation, actuator motor, and connections.
Electrical failure	Blown fuse, poor ground, faulty component	Check main fuse (30A), inspect ground connections, test components.
Overheating	Low oil level, dirty cooling fins, lean fuel mixture	Check oil, clean cylinder fins, inspect carburetor jetting.

Wiring Diagrams

Complete color-coded wiring diagrams for the entire electrical system are provided in the full manual. Refer to the diagram for wire colors, connector locations, and circuit paths when diagnosing electrical faults.

Note: Always disconnect the battery negative terminal before working on the electrical system.

Storage & Transport

Proper procedures for long-term storage and safe transport.

Storage Preparation: Fill fuel tank and add fuel stabilizer. Run engine for 5 minutes. Change engine oil. Remove battery and store on a tender. Inflate tires to recommended pressure. Store in a cool, dry place.
Transport: Secure the ATV using high-quality tie-downs on the frame or designated points—not on suspension or handlebars. Place transmission in PARK. Set parking brake.

CAUTION! Never transport with fuel in the tank near an open flame or in an enclosed space without proper ventilation.

Safety & Warnings

This ATV 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 a passenger on a single-rider ATV.
Never operate on public roads or paved surfaces (unless designated).
Never operate under the influence of drugs or alcohol.
Complete a training course. Supervise riders under 16.
Inspect your ATV before each use.
Ride within your limits and on terrain appropriate for your skill level.

For technical support or to order parts, contact an authorized Yamaha dealer or visit Yamaha's official website.