Yamaha Moto-4 & Big Bear 1987-2004 (ECM490)

This Yamaha ATV manual is 680 pages.

QUICK REFERENCE DATA

CHAPTER ONE / GENERAL INFORMATION
Manual organization / Notes, cautions and warnings / Safety first / Service hints / Washing the vehicle / Special tips / Torque specifications / Fasteners / Lubricants / RTV gasket sealant / Gasket remover / Threadlocking compound / Expendable supplies / Serial numbers / Warning and information labels / Basic hand tools / Precision measuring tools / Test equipment / Special tools / Fabricating tools / Mechanic’s tips / Bearing replacement / Seals / Riding safety / Off Road rules / Storage / Specifications

CHAPTER TWO / TROUBLESHOOTING
Operating requirements / Troubleshooting instruments / Starting the engine / Starting difficulties / Engine starting troubles / Engine is difficult to start / Poor idle speed performance / poor medium to high speed performance / Starting system / Charging system / Ignition system / Fuel system / Engine overheating (1987-1998 2-wheel drive and 1987-1997 4-wheel drive models) / Engine noises / Engine leak down test / Clutch / Transmission / Drive train noise / Handling / Frame noise / Brakes

CHAPTER THREE / LUBRICATION, MAINTENANCE AND TUNE-UP
Pre-ride check list / Maintenance service schedule intervals / Periodic lubrication / Engine oil and filter change / Front differential gearcase oil change / Rear final drive gearcase oil change / Control cable lubrication / Non-schedule lubrication / Periodic maintenance / Non-scheduled maintenance / Tune-up / Air filter / Valve clearance / Cylinder compression / Spark plug / Ignition timing / Pilot air screw adjustment / Idle speed adjustment / Storage /Specifications

CHAPTER FOUR / ENGINE TOP END
Cylinder head / Decompression camshaft / Camshaft and rocker arms / Camshaft chain / Chain guides / Valves and components / Cylinder block / Piston and rings /Specifications

CHAPTER FIVE / ENGINE BOTTOM END
Removal installation / Middle drive gear / Transfer gear assembly / Balancer gear and oil pump drive gear assembly / Oil pump / Internal oil pipe / External oil pipe / Oil cooler / Magneto stator and stator housing / Magneto rotor and starter clutch / Crankcase and crankshaft / Recoil starter / Break-in /Specifications

CHAPTER SIX / CLUTCH AND EXTERNAL SHIFT MECHANISM
Clutch cover / Clutch release lever mechanism / One-way clutch check / External shift mechanism /Specifications

CHAPTER SEVEN / TRANSMISSION, SELECT LEVER AND INTERNAL SHIFT MECHANISM
Transmission reverse system identification / Middle drive shaft / Reverse gear and shaft / High/low combination gear assembly / Internal shift mechanism / Transmission range select lever /Specifications

CHAPTER EIGHT / FUEL AND EXHAUST SYSTEMS
Carburetor / Carburetor adjustments / Throttle cable / Throttle lever housing / Fuel tank / Fuel shutoff valve / Air filter air box / Exhaust system /Specifications

CHAPTER NINE / ELECTRICAL SYSTEM
Charging system / Stator charging coil / Voltage regulator/rectifier / Capacitor discharge ignition / Ignition coil / CDI magneto (stator source and pickup coils) / Starting system / Starter relay / Lighting system / Indicator light system / Meter / Switches / Relays / Fuse / Circuit breaker / Wiring diagrams /Specifications

CHAPTER TEN / FRONT SUSPENSION AND STEERING
Front wheel / Front hub brake drum / Front spindle / Front suspension / Shock absorber / Steering knuckle / Control arm / Handlebar / Tie rods / Steering shaft / Tires and wheels /Specifications

CHAPTER ELEVEN / FRONT DRIVE MECHANISM FOUR-WHEEL DRIVE
Front axle / Front differential gearcase / Front drive shaft /Specifications

CHAPTER TWELVE / REAR SUSPENSION
Rear wheels / Rear hub / Brake drum / Rear axle / Final drive unit and short drive shaft / Shock absorber / Swing arm /Specifications

CHAPTER THIRTEEN / BRAKES
Front brake / Front drum brake / Front master cylinder / Rear brake disc / Rear drum brake hub / Front brake hose / Rear brake pedal / Brake bleeding /Specifications

CHAPTER FOURTEEN / BODY
Seat / Front guard / Front bumper / Front carrier/rack / Rear carrier/rack / Rear guard / Fuel tank cover assembly / Front fender / Rear fender / Foot rests /Specifications

SUPPLEMENT / 1999-ON 2-WHEEL DRIVE, 1998-ON 4-WHEEL DRIVE MODEL SERVICE INFORMATION

INDEX

WIRING DIAGRAMS

Models covered:
1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 Yamaha YFM350 2-WD YFM 350 2 two wheel drive
1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 Yamaha YFM350FW 4-WD YFM 350FW YFM 350 FW four wheel drive 4
2000 2001 2002 2003 2004 Yamaha YFM400 2-WD YFM 400 2 two wheel drive
2000 2001 2002 2003 2004 Yamaha YFM400FW 4-WD YFM 400FW YFM 400 FW Four wheel drive 4

Clymer Yamaha YFM350 Moto-4 Two Wheel Drive 2X4 Manual
Clymer Yamaha YFM350FW Moto-4 Four Wheel Drive 4X4 Manual
Clymer Yamaha YFM400 Big Bear Two Wheel Drive 2X4 Manual
Clymer Yamaha YFM400FW Big Bear Four Wheel Drive 4X4 Manual

YFM350 Moto-4 2-WD (1987-1999)
YFM350FW Moto-4 4-WD (1987-1999)
YFM400 Big Bear 2-WD (2000-2004)
YFM400FW Big Bear 4-WD (2000-2004)