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READ THIS MANUAL CAREFULLY!
It contains important safety information.
OWNER'S MANUAL
YFM400NN
WARNING
This ATV should not be ridden by anyone under 16 years of age.
LIT-11626-14-22
5GW-F8199-11

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Summary of Contents for Yamaha BIG BEAR YFM400NN

  • Page 1 READ THIS MANUAL CAREFULLY! It contains important safety information. OWNER’S MANUAL YFM400NN WARNING This ATV should not be ridden by anyone under 16 years of age. LIT-11626-14-22 5GW-F8199-11...
  • Page 3 Yamaha experience in the production of fine sporting, touring, and pace-set- ting racing machines. With the purchase of this Yamaha, you can now appreciate the high degree of craftsmanship and reliability that have made Yamaha a leader in these fields.
  • Page 4: Warning

    EBU00010 IMPORTANT MANUAL INFORMATION FAILURE TO FOLLOW THE WARNINGS CONTAINED IN THIS MANUAL CAN RESULT IN SERIOUS INJURY OR DEATH. Particularly important information is distinguished in this manual by the following nota- tions: The Safety Alert Symbol means ATTENTION! BECOME ALERT! YOUR SAFETY IS INVOLVED! Failure to follow WARNING instructions could result in severe injury WARNING...
  • Page 5 Please check your local riding laws and regulations before operating this machine. EBU00531 YFM400NN OWNER’S MANUAL AFFIX DEALER © 2000 by Yamaha Motor Corporation, U.S.A. LABEL HERE 1st Edition, April 2000 All rights reserved. Any reprinting or unauthorized use without the written...
  • Page 6: Table Of Contents

    EBU00014 CONTROL FUNCTIONS....4-1 WARNING Main switch........4-1 Indicates a potential hazard that could Indicator lights........4-2 result in serious injury or death. Oil temperature warning light checking method ......4-3 Fuel gauge ........4-4 CONTENTS Handlebar switches .......4-5 Throttle lever ........4-6 Speed limiter ........4-7 LOCATION OF THE WARNING Front brake lever ......4-8 AND SPECIFICATION LABELS ..1-1...
  • Page 7 Front shock absorber OPERATION........6-1 adjustment ........4-17 Starting a cold engine ....6-1 Rear shock absorber Starting a warm engine....6-3 adjustment ........4-18 Warming up........6-3 Auxiliary DC jack......4-19 Reverse knob operation and reverse driving ......6-4 PRE-OPERATION CHECKS ..... 5-1 Shifting..........6-5 Front and rear brakes ....
  • Page 8 Crossing through shallow Front brake fluid level water ...........7-34 inspection........8-20 Riding over rough terrain....7-36 Brake fluid replacement ....8-21 Sliding and skidding....7-38 Rear brake pedal and lever What to do if.........7-40 adjustment........8-23 What to do ........7-40 Clutch adjustment ......8-26 Cable inspection and PERIODIC MAINTENANCE AND lubrication ........8-27 ADJUSTMENT .........8-1...
  • Page 9 CLEANING AND STORAGE.... 9-1 A. Cleaning ........9-1 B. Storage ........9-3 SPECIFICATIONS......10-1 NOISE REGULATION ....11-1 MAINTENANCE RECORD ..... 12-1 ATV LIMITED WARRANTY ... 13-1 YAMAHA EXTENDED SERVICE (Y.E.S.) ..........14-1...
  • Page 10: Location Of The Warning And Specification Labels

    EBU00464 LOCATION OF THE WARNING AND SPECIFICATION LABELS...
  • Page 11 They contain important in- formation for safe and proper operation of your ATV. Never remove any labels from your ATV. If a label becomes difficult to read or comes off, a replacement label is available from your Yamaha dealer.
  • Page 14: Safety Information

    EBU00017 SAFETY INFORMATION AN ATV IS NOT A TOY AND CAN BE HAZARDOUS TO OPERATE. An ATV handles differ- ently from other vehicles including motorcycles and cars. A collision or rollover can occur quickly, even during routine maneuvers such as turning and riding on hills or over obsta- cles, if you fail to take proper precautions.
  • Page 15 Always avoid operating an ATV on any paved surfaces, including sidewalks, drive- ● ways, parking lots and streets. ● Never operate an ATV on any public street, road or highway, even a dirt or gravel one. Never operate an ATV without wearing an approved motorcycle helmet that fits prop- ●...
  • Page 16 ● Always follow proper procedures for turning as described in this manual. Practice turning at low speeds before attempting to turn at faster speeds. Do not turn at exces- sive speed. ● Never operate the ATV on hills too steep for the ATV or for your abilities. Practice on smaller hills before attempting larger hills.
  • Page 17 Always use proper procedures if you stall or roll backwards when climbing a hill. To ● avoid stalling, use proper gear and maintain a steady speed when climbing a hill. If you stall or roll backwards, follow the special procedure for braking described in this manual.
  • Page 18 ● Always use the size and type tires specified in this manual. Always maintain proper tire pressure as described in this manual. Never modify an ATV through improper installation or use of accessories. ● ● Never exceed the stated load capacity for an ATV. Cargo should be properly distribut- ed and securely attached.
  • Page 19 WARNING When transporting the machine in an- other vehicle, be sure it is kept upright POTENTIAL HAZARD and that the fuel cock is in the “OFF” po- Improper handling of gasoline. sition. Otherwise, fuel may leak out of WHAT CAN HAPPEN the carburetor or fuel tank.
  • Page 20 WARNING POTENTIAL HAZARD Starting or running the engine in a closed area. WHAT CAN HAPPEN Exhaust fumes are poisonous and may cause loss of consciousness and death within a short time. HOW TO AVOID THE HAZARD Always operate your machine in an area with adequate ventilation.
  • Page 21: Description And Machine Identification

    EBU00032 DESCRIPTION AND MACHINE IDENTIFICATION 1. Rear carrier 11. Rear brake lever 2. Seat 12. Parking brake lock plate 3. Front carrier 13. Starter (choke) 4. Rear brake pedal 14. Reverse knob 5. Headlight 15. Front brake lever 6. Fuel cock 16.
  • Page 22: Identification Number Records

    This number can be used for order- sistance when ordering spare parts from a ing a new key. Yamaha dealer or for reference in case the vehicle is stolen. 1. KEY IDENTIFICATION NUMBER: 2. VEHICLE IDENTIFICATION NUMBER: 1.
  • Page 23: Vehicle Identification Number

    Record the information on this label in the space provided. This information will be needed to order spare parts from your Yamaha dealer. 1. Vehicle identification number NOTE: The vehicle identification number is used 1. Model label...
  • Page 24: Control Functions

    EBU00039 CONTROL FUNCTIONS WARNING Indicates a potential hazard that could result in serious injury or death. EBU00041 Main switch Functions of the respective switch posi- tions are as follows: Engine can be started only at this position and the headlight and taillight come on when the light switch is on.
  • Page 25: Indicator Lights

    EBU00043 EBU00732 Indicator lights Oil temperature warning light “OIL TEMP” When the oil temperature reaches a speci- fied level, this light comes on to warn that the engine oil temperature is too hot. If the warning light comes on during operation, stop the engine as soon as it is safe to do so and allow the engine to cool down for about 10 minutes.
  • Page 26: Oil Temperature Warning Light Checking Method

    Allow to cool. Engine oil temperature Ask a Yamaha dealer to and electrical circuit are inspect the electrical circuit. OK. Go ahead with riding.
  • Page 27: Fuel Gauge

    EBU00052 Fuel gauge The fuel gauge indicates the amount of fuel in the fuel tank. When the needle reaches the red line, refill the tank at the first opportunity. 1. Fuel gauge NOTE: If the machine runs out of fuel, move the fuel cock lever to the “RES”...
  • Page 28: Handlebar Switches

    EBU00053 EBU00055* Handlebar switches Start switch “ ” The starter motor cranks the engine when this switch is pushed. CAUTION: See starting instructions prior to starting engine. (see page 6-1 for details) EBU00734 Light switch “LIGHTS” Turn the switch to the “LO” position to switch on the low beam and the taillight.
  • Page 29: Throttle Lever

    Check the operation of the throttle lever before you start the engine. If it does not work smoothly, check for the cause. Correct the problem before riding the ATV. Consult a Yamaha dealer if you can’t find or solve the problem yourself. 1. Throttle lever...
  • Page 30: Speed Limiter

    EBU00066 Speed limiter WARNING The speed limiter keeps the throttle from POTENTIAL HAZARD fully opening, even when the throttle lever Improper adjustment of the speed limit- is pushed to the maximum. Screwing in er and throttle. the adjuster limits the maximum engine WHAT CAN HAPPEN power available and decreases the maxi- The throttle cable could be damaged.
  • Page 31: Front Brake Lever

    EBU00070 Front brake lever The front brake lever is located on the right handlebar. Pull it toward the handlebar to apply the front brake. 1. Rear brake pedal 1. Front brake lever EBU00073 Rear brake pedal and lever The brake pedal is located on the right side of the machine and the brake lever is locat- ed on the left handlebar.
  • Page 32: Parking Brake

    EBU00074 Parking brake WARNING Use the parking brake when you have to POTENTIAL HAZARD start the engine or park the machine, espe- Improper use of the parking brake. cially on a slope. Apply the rear brake lever WHAT CAN HAPPEN and push down the lock plate to apply the The ATV could start moving unexpect- parking brake.
  • Page 33: Shift Pedal

    EBU00084 EBU00747 Shift pedal Reverse knob This machine is equipped with a constant- The reverse knob is used to shift into re- mesh 5-speed forward and 1-speed re- verse gear. verse transmission. The shift pedal is locat- Refer to the “Reverse knob operation and ed on the left side of the engine.
  • Page 34: Recoil Starter

    EBU00590 Recoil starter WARNING Firmly grasp the handle and pull slightly POTENTIAL HAZARD until engagement can be felt. Then pull Starting the engine in gear and/or start- forcefully, being careful not to pull the rope ing the engine without setting the park- all the way out.
  • Page 35: Fuel Tank Cap

    EBU00092 Fuel tank cap Remove the fuel tank cap by turning it counterclockwise. 1. Fuel tank cap 4-12...
  • Page 36: Fuel Cock

    EBU00093 Fuel cock The fuel cock supplies fuel from the fuel tank to the carburetor. The fuel cock has three positions. OFF: With the lever in this position fuel will not flow. Always turn the lever to this position when the engine is not running.
  • Page 37: Starter (Choke)

    EBU00095 Starter (choke) “ ” Starting a cold engine requires a richer air- fuel mixture. A separate starter circuit sup- plies this mixture. Move in direction to turn on the starter (choke). Move in direction to turn off the starter (choke).
  • Page 38: Seat

    EBU00567 Seat To remove the seat, pull the seat lock lever upward and pull up the seat at the rear. 1. Seat lock lever To install the seat, insert the projections on the front of the seat into the seat holders and push down on the seat at the rear.
  • Page 39: Storage Box

    EBU00581 EBU00582 Storage box Front carrier Maximum load limit: 2 kg (4.4 lb) Maximum load limit: 40 kg (88 lb) CAUTION: EBU00583 To protect from damage, do not put metal Rear carrier products, like tools or sharply edged prod- Maximum load limit: 80 kg (176 lb) ucts directly in the storage box.
  • Page 40: Front Shock Absorber Adjustment

    EBU00635 Front shock absorber adjustment Standard position: B The spring preload can be adjusted to suit A - Minimum (Soft) the rider’s weight and riding conditions. E - Maximum (Hard) Adjust the spring preload as follows: To increase the spring preload, turn the ad- WARNING juster in direction POTENTIAL HAZARD...
  • Page 41: Rear Shock Absorber Adjustment

    EBU00634 Rear shock absorber adjustment Standard position: B The spring preload can be adjusted to suit A - Minimum (Soft) the rider’s weight and riding conditions. E - Maximum (Hard) Adjust the spring preload as follows: To increase the spring preload, turn the ad- juster in direction To decrease the spring preload, turn the adjuster in direction...
  • Page 42: Auxiliary Dc Jack

    EBU00748 Auxiliary DC jack The auxiliary DC jack is located at the front right side of the ATV. The auxiliary DC jack can be used for suitable work lights, radi- os, etc. The auxiliary DC jack can only be used when the main switch is in the “ON” position.
  • Page 43 CAUTION: ● Do not use accessories requiring more than the above maximum capacity. This may overload the circuit and cause the fuse to blow. If accessories are used without the en- ● gine running or with the headlight turned on, the battery will lose its charge and engine starting may be- come difficult.
  • Page 44: Pre-Operation Checks

    PRE-OPERATION CHECKS Before using this machine, check the following points: ITEM ROUTINE PAGE • Check operation, free play, fluid level and fluid leakage. Front brake 5-3 ~ 5-4, • Fill with DOT 4 brake fluid if necessary. 8-19 ~ 8-25 Rear brake •...
  • Page 45 WARNING POTENTIAL HAZARD Failure to inspect the ATV before oper- ating. Failure to properly maintain the ATV. WHAT CAN HAPPEN Increases the possibility of an accident or equipment damage. HOW TO AVOID THE HAZARD Always inspect your ATV each time you use it to make sure the ATV is in safe op- erating condition.
  • Page 46: Front And Rear Brakes

    They should move smooth- is any leakage, the brake system ly and there should be a firm feeling should be inspected by a Yamaha when the brake is applied. If not, have dealer. the machine inspected by a Yamaha 4.
  • Page 47 Always check the brakes at the start of every ride. Do not ride the ATV if you find any problem with the brakes. If a problem cannot be corrected by the ad- justment procedures provided in this manual, have the ATV inspected by a Yamaha dealer.
  • Page 48: Fuel

    15 L (3.3 Imp gal, 4.0 US gal) formance problems. Reserve: 4.0 L (0.9 Imp gal, 1.1 US gal) Your Yamaha engine has been designed to use regular unleaded gasoline with a pump octane number ([R+M]/2) of 86 or higher, or research octane number of 91 or higher.
  • Page 49 WARNING POTENTIAL HAZARD Improper care when refueling. WHAT CAN HAPPEN Fuel can spill, which can cause a fire and severe injury. Fuel expands when it heats up. If the fuel tank is overfilled, fuel could spill out due to heat from the engine or the sun. HOW TO AVOID THE HAZARD Do not overfill the fuel tank.
  • Page 50: Engine Oil

    EBU00484 Engine oil CAUTION: Make sure the engine oil is at the specified Be sure to use motor oils that do not con- level. Add oil as necessary. (See page 8-5 ~ tain anti-friction modifiers. 8-8.) Passenger car motor oils (often labeled “Energy Conserving”) contain anti-friction Recommended oil: additives which will cause clutch and/or...
  • Page 51: Final Gear Oil

    Take the ma- NOTE: chine to a Yamaha dealer or refer to the Ser- GL-4 is a quality and additive rating, GL-5 vice Manual for correct tightening torque. or GL-6 rated hypoid gear oils may also be...
  • Page 52: Lights

    Repair as necessary for proper control, increasing your risk of accident. operation. HOW TO AVOID THE HAZARD 1. The tires listed below have been ap- proved by Yamaha Motor Co., Ltd. for this model. Other tire combinations are not recommended. Manufacturer Size...
  • Page 53 2. The tires should be set to the recom- 4. Use no more than the following pres- mended pressure: sures when seating the tire beads. Recommended tire pressure Front 250 kPa (2.5 kgf/cm , 36 psi) ● Front 25 kPa (0.25 kgf/cm , 3.6 psi) Rear 250 kPa (2.5 kgf/cm , 36 psi)
  • Page 54: How To Measure Tire Pressure

    EBU00159 How to measure tire pressure Use the low-pressure tire gauge. NOTE: The low-pressure tire gauge is included as standard equipment. Make two measure- ments of the tire pressure and use the sec- ond reading. Dust or dirt in the gauge could cause the first reading to be incor- rect.
  • Page 55: Tire Wear Limit

    EBU00160 Tire wear limit When the tire groove decreases to 3 mm (0.12 in) due to wear, replace the tire. a. 3 mm (0.12 in) 5-12...
  • Page 56: Operation

    2. Turn the fuel cock to “ON”. there is a control or function you do not 3. Turn the main switch to “ON” and the understand, ask your Yamaha dealer. engine stop switch to “ ”. 4. Shift the transmission into neutral.
  • Page 57 (80 ˚F) and warm engine start on. If the light does not come on, ask a position. Yamaha dealer to inspect it. The engine can be started in any gear ● if the rear brake lever is applied. How- ever, it is recommended to shift into neutral before starting the engine.
  • Page 58: Starting A Warm Engine

    NOTE: CAUTION: If the engine fails to start, release the ● See the “Engine break-in” section prior to start switch, then push the start switch operating engine for the first time. again. Pause a few seconds before the next attempt. Each cranking should be as short as possible to preserve bat- EBU00180 tery energy.
  • Page 59: Reverse Knob Operation And

    If the light does not come on, CAUTION: ask a Yamaha dealer to inspect the machine. Before shifting, stop the machine and re- 4. Check behind you for people or obsta- turn the throttle lever to its closed posi- cles, then release the rear brake lever.
  • Page 60: Shifting

    EBU00201 Shifting CAUTION: This model has a 5-speed forward and Do not coast for long periods with the en- 1-speed reverse transmission with centrif- gine off, and do not tow the machine a ugal automatic clutch. The transmission al- long distance. Even with gears in neutral, lows you to control the amount of power the transmission is only properly lubricat- you have available at a given speed or for...
  • Page 61: To Decelerate

    EBU00207 4. Once the machine has attained ade- To decelerate quate speed, release the throttle lever. When slowing down or stopping, release the throttle and apply the brakes smoothly 5. Shift into second gear and release the and evenly. As you slow down, shift to a shift pedal.
  • Page 62: Engine Break-In

    Because the If any abnormality is noticed during this engine is brand new, you must not put an period, consult a Yamaha dealer. excessive load on it for the first several 1. 0 ~ 10 hours: hours of running.
  • Page 63: Parking

    EBU00211 2. 10 ~ 20 hours: Parking Avoid prolonged operation above 3/4 When parking, stop the engine and shift throttle. the machine freely into neutral. Turn the fuel cock to “OFF” through the gears but do not use full and apply the parking brake. throttle at any time.
  • Page 64: Parking On A Slope

    EBU00219 Parking on a slope 1. Bring the machine to a stop by apply- ing the brakes in low gear. WARNING 2. Stop the engine. POTENTIAL HAZARD 3. With the rear brake lever and pedal ap- Parking on a hill or other incline. plied, apply the parking brake and slowly release the rear brake pedal.
  • Page 65: Accessories And Loading

    Choose only accessories designed for ● not limited to) a heavy or bulky object at- your ATV. Your Yamaha dealer has a va- tached to the handlebars which could riety of genuine Yamaha accessories. make steering difficult, an accessory that...
  • Page 66 EBU00588 Loading ● Do not exceed the maximum tongue Cargo or a trailer can change the stability weight. You can measure tongue weight and handling of an ATV. with a bathroom scale. Put the tongue of You must use common sense and good the loaded trailer on the scale with the judgment when carrying cargo or towing a tongue at hitch height.
  • Page 67 ● Ride more slowly than you would with- WARNING out a load. The more weight you carry, POTENTIAL HAZARD the slower you should go. Although con- Overloading this ATV or carrying or ditions vary, it is good practice not to ex- towing cargo improperly.
  • Page 68 EBU00543 WARNING Indicates a potential hazard that could result in serious injury or death. 6-13...
  • Page 69: Riding Your Atv

    RIDING YOUR...
  • Page 70: Getting To Know Your Atv

    WARNING Indicates a potential hazard that could re- sult in serious injury or death. GETTING TO KNOW YOUR ATV achieve the skill necessary to enjoy riding This ATV is mainly for utility use, but may safely. Before you begin to ride, be sure also be used for recreation.
  • Page 71: Ride With Care And Good Judgement

    Beginning and inexperienced operators Get training if you are inexperienced. should complete the certified training Beginners should get training from a certi- course offered by Yamaha. They should fied instructor. then regularly practice the skills learned Become familiar with this ATV at slow...
  • Page 72 Not recommended for children under 16 years of age. WARNING POTENTIAL HAZARD Failure to follow the age recommenda- tions for this ATV. WHAT CAN HAPPEN Use by children of ATVs that are not rec- ommended for their age can lead to se- vere injury or death of the child.
  • Page 73 This machine is designed to carry operator and cargo only - passengers prohibited. WARNING POTENTIAL HAZARD Carrying a passenger on this ATV. WHAT CAN HAPPEN Greatly reduces your ability to balance and control this ATV. Could cause an ac- cident, resulting in harm to you and/or your passenger.
  • Page 74 Apparel Operating without protective clothing increases your chances of severe injury WARNING in the event of an accident. POTENTIAL HAZARD HOW TO AVOID THE HAZARD Operating this ATV without wearing an Always wear an approved motorcycle approved motorcycle helmet, eye pro- helmet that fits properly.
  • Page 75 Do not operate after consuming alcohol or WARNING drugs. POTENTIAL HAZARD Operator’s performance capability is re- Operating this ATV after consuming al- duced by the influence of alcohol or drugs. cohol or drugs. WHAT CAN HAPPEN Could seriously affect your judgment. Could cause you to react more slowly.
  • Page 76 Pre-operation checks WARNING Always perform the pre-operation checks POTENTIAL HAZARD listed on page 5-1 before riding for safety Operating this ATV with improper tires, and proper care of the machine. or with improper or uneven tire pres- WARNING sure. POTENTIAL HAZARD WHAT CAN HAPPEN Failure to inspect the ATV before oper- Use of improper tires on this ATV, or op-...
  • Page 77 Speed limiter WARNING For riders inexperienced with this model, Indicates a potential hazard that could this model is equipped with a speed limiter result in serious injury or death. in the throttle lever housing. The speed Do not operate at speeds too fast for your limiter limits the power and top speed of skills or the conditions.
  • Page 78 Loading and accessories WARNING Use extra caution when riding the machine POTENTIAL HAZARD with additional loads, such as accessories Overloading this ATV or carrying or or cargo. The machine’s handling may be towing cargo improperly. adversely affected. Reduce your speed WHAT CAN HAPPEN when adding additional loads.
  • Page 79 During operation WARNING Always keep your feet on the footboards POTENTIAL HAZARD during operation. Otherwise your feet may Removing hands from handlebars or contact the rear wheels. feet from footboards during operation. WHAT CAN HAPPEN Removing even one hand or foot can re- duce your ability to control the ATV or could cause you to lose your balance and fall off of the ATV.
  • Page 80 Avoid wheelies and jumping. You may lose control of the machine or overturn. WARNING POTENTIAL HAZARD Attempting wheelies, jumps, and other stunts. WHAT CAN HAPPEN Increases the chance of an accident, in- cluding an overturn. HOW TO AVOID THE HAZARD Never attempt stunts, such as wheelies or jumps.
  • Page 81 Never modify this ATV through improp- er installation or use of accessories. All parts and accessories added to this ve- hicle should be genuine Yamaha or equivalent components designed for use on this ATV and should be installed and used according to instructions. If you have questions, consult an autho- rized ATV dealer.
  • Page 82 Exhaust system The exhaust system on the machine is very hot during and following operation. To prevent burns, avoid touching the exhaust system. Park the machine in a place where pedestrians or children are not likely to touch it. WARNING POTENTIAL HAZARD Hot exhaust system.
  • Page 83: Be Careful Where You Ride

    BE CAREFUL WHERE YOU RIDE This machine is designed for off-road use only. Riding on paved surfaces can cause loss of control. WARNING POTENTIAL HAZARD Operating this ATV on paved surfaces. WHAT CAN HAPPEN ATVs are designed for off-road use only. Paved surfaces may seriously affect handling and control of the ATV, and may cause the vehicle to go out of con-...
  • Page 84 Do not ride on any public road, street, or highway. Riding on public roads can result in colli- sions with other vehicles. WARNING POTENTIAL HAZARD Operating this ATV on public streets, roads or highways. WHAT CAN HAPPEN You can collide with another vehicle. HOW TO AVOID THE HAZARD Never operate this ATV on any public street, road or highway, even a dirt or...
  • Page 85 Know the terrain where you ride. Ride cau- tiously in unfamiliar areas. Stay alert for holes, rocks, or roots in the terrain, and other hidden hazards which may cause the machine to upset. WARNING POTENTIAL HAZARD Failure to use extra care when operating this ATV on unfamiliar terrain.
  • Page 86 WARNING POTENTIAL HAZARD Failure to use extra care when operating on excessively rough, slippery or loose terrain. WHAT CAN HAPPEN Could cause loss of traction or vehicle control, which could result in an acci- dent, including an overturn. HOW TO AVOID THE HAZARD Do not operate on excessively rough, slippery or loose terrain until you have learned and practiced the skills neces-...
  • Page 87 When riding in an area where you might WHAT CAN HAPPEN not easily be seen, such as desert terrain, You could be in a collision. You could be mount a caution flag on the machine. DO injured. NOT use the flag pole bracket as a trailer HOW TO AVOID THE HAZARD hitch.
  • Page 88 Select a large, flat area off-road to become With the engine idling, lift the shift pedal to familiar with your ATV. Make sure that this the 1st gear position and then release the area is free of obstacles and other riders. parking brake.
  • Page 89 WARNING CAUTION: Do not shift gears without releasing the POTENTIAL HAZARD throttle. Damage to the engine or drive Engaging a lower gear when the engine train may occur. speed is too high. WHAT CAN HAPPEN When slowing down or stopping, release The wheels could stop rotating.
  • Page 90: Turning Your Atv

    TURNING YOUR ATV HOW TO AVOID THE HAZARD To achieve maximum traction while riding Always follow proper procedures for off-road, the two rear wheels are mounted turning as described in this Owner’s solidly on one axle and turn together at the Manual.
  • Page 91 Once you have learned this technique you should be able to perform it at higher speeds or in tighter curves. Improper riding procedures such as abrupt throttle changes, excessive braking, incor- rect body movements, or too much speed for the sharpness of the turn may cause the ATV to tip.
  • Page 92: Climbing Uphill

    CLIMBING UPHILL HOW TO AVOID THE HAZARD Use proper riding techniques to avoid ve- Never operate the ATV on hills too hicle overturns on hills. Be sure that you steep for the ATV or for your abilities. can maneuver your ATV well on flat Practice on smaller hills before attempt- ground before attempting any incline and ing large hills.
  • Page 93 WARNING An obstacle, a sharp drop, or another vehicle or person could be on the other POTENTIAL HAZARD side of the hill. Climbing hills improperly. WHAT CAN HAPPEN Could cause loss of control or cause the ATV to overturn. HOW TO AVOID THE HAZARD Always follow proper procedures for climbing hills as described in this Own- er’s Manual.
  • Page 94 If you are climbing a hill and you find that When crossing the side of a hill: you have not properly judged your ability Always follow proper procedures as de- to make it to the top, you should turn the scribed in the Owner’s Manual.
  • Page 95 If your ATV has stalled or stopped and you WARNING believe you can continue up the hill, restart POTENTIAL HAZARD carefully to make sure you do not lift the Stalling, rolling backwards or improper- front wheels which could cause you to lose ly dismounting while climbing a hill.
  • Page 96 Dismount on uphill side or to a side if pointed straight uphill. Turn the ATV around and remount, following the pro- cedure described in the Owner’s Manu- 7-29...
  • Page 97: Riding Downhill

    RIDING DOWNHILL WARNING When riding your ATV downhill, shift your POTENTIAL HAZARD weight as far to the rear and uphill side of Going down a hill improperly. the ATV as possible. Move back on the seat WHAT CAN HAPPEN and sit with your arms straight. Choose a Could cause loss of control or cause low gear which will allow the engine com- ATV to overturn.
  • Page 98 7-31...
  • Page 99: Crossing A Slope

    CROSSING A SLOPE If your ATV does begin to tip over, gradual- Traversing a sloping surface on your ATV ly steer in the downhill direction if there requires you to properly position your are no obstacles in your path. As you re- weight to maintain proper balance.
  • Page 100 When crossing the side of a hill: Always follow proper procedures as de- scribed in the Owner’s Manual. Avoid hills with excessively slippery or loose surfaces. Shift your weight to the uphill side of the ATV. 7-33...
  • Page 101: Crossing Through Shallow Water

    CROSSING THROUGH SHALLOW WATER Remember that wet brakes may have The ATV can be used to cross slow mov- reduced stopping ability. Test your ing, shallow water of up to a maximum of brakes after leaving water. If necessary, 35 cm (14 inches) in depth. Before entering apply them several times to let friction the water, choose your path carefully.
  • Page 102 Test your brakes after leaving the water. CAUTION: Do not continue to ride your ATV without After riding your ATV in water, be sure to verifying that you have regained proper drain the trapped water by removing the braking ability. check hose at the bottom of the air filter case.
  • Page 103: Riding Over Rough Terrain

    RIDING OVER ROUGH TERRAIN WARNING Riding over rough terrain should be done POTENTIAL HAZARD with caution. Look out for obstacles which Improperly operating over obstacles. could cause damage to the ATV or could WHAT CAN HAPPEN lead to an upset or accident. Be sure to Could cause loss of control or a colli- keep your feet firmly mounted on the foot- sion.
  • Page 104: Sliding And Skidding

    SLIDING AND SKIDDING If the rear wheels of your ATV start to slide Care should be used when riding on loose sideways, control can usually be regained or slippery surfaces since the ATV may (if there is room to do so) by steering in the slide.
  • Page 105 With practice, over a period of time, skill at WARNING controlled sliding can be developed. The POTENTIAL HAZARD terrain should be chosen carefully before Skidding or sliding improperly. attempting such maneuvers, since both WHAT CAN HAPPEN stability and control are reduced. Bear in You may lose control of this ATV.
  • Page 106: What To Do If

    WHAT TO DO IF ... ● If your ATV starts to slide sideways: This section is designed to be a reference Steer in the direction of the slide if you guide only. Be sure to read each section on have the room. riding techniques completely.
  • Page 107 If your ATV is traversing a sloping sur- ● face: Be sure to ride with your weight posi- tioned towards the uphill side of the ATV to maintain proper balance. If the ATV starts to tip, steer down the hill (if there are no obstacles in your way) to regain balance.
  • Page 108: Periodic Maintenance And Adjustment

    EBU00515 PERIODIC MAINTENANCE AND Have a Yamaha dealer perform service if ADJUSTMENT you are not familiar with machine ser- vice. Periodic inspection, adjustment and lubri- cation will keep your machine in the safest and most efficient condition possible. EBU00535 Safety is an obligation of the machine Owner’s manual and tool kit...
  • Page 109 If you do not have a torque wrench avail- you have questions, consult an autho- able during a service operation requiring rized Yamaha ATV dealer. one, take your machine to a Yamaha deal- er to check the torque settings and adjust them as necessary.
  • Page 110: Periodic Maintenance/Lubrication

    EBU00261 PERIODIC MAINTENANCE/LUBRICATION INITIAL EVERY ITEM ROUTINE month months months months year • Check valve clearance. Valves* • Adjust if necessary. • Check condition. Spark plug • Adjust gap and clean. • Replace if necessary. • Clean. Every 20~40 hours Air filter •...
  • Page 111 Drive shaft universal joint* • Lubricate. • Check all chassis fittings and fasteners. Fittings and Fasteners* • Correct if necessary. * It is recommended that these items be serviced by a Yamaha dealer. NOTE: Brake fluid replacement: 1. When disassembling the master cylin- der or caliper cylinder, replace the brake fluid.
  • Page 112: Engine Oil

    EBU00772 Engine oil 4. Remove the dipstick, and then check Engine oil level measurement the oil level. 1. Place the ATV on a level surface. 5. The oil level should be between the 2. Warm up the engine for several min- maximum and minimum marks.
  • Page 113: Engine Oil Replacement/Oil Filter Element Cleaning

    Engine oil replacement and oil filter ele- ment cleaning 1. Place the ATV on a level surface. 2. Warm up the engine for several min- utes, and then stop it. 3. Place a container under the engine. 4. Remove the dipstick, and then remove the drain bolt to drain the oil.
  • Page 114 6. Clean the oil strainer and oil filter with Tightening torque: solvent. Drain bolt (engine): 7. Check the O-ring for damage and re- 32 Nm (3.2 m·kg, 23 ft·lb) place it if necessary. Filter cover bolt: 8. Install the oil filter, O-ring, oil filter cov- 10 Nm (1.0 m·kg, 7.2 ft·lb) er, oil strainer, compression spring and drain bolt.
  • Page 115 10. Warm up the engine for several min- utes at idle speed. Check for oil leak- age while warming up. CAUTION: If oil leakage is found, stop the engine im- mediately and check for the cause. Oil pressure check 1. Put a cloth around the cylinder. 1.
  • Page 116: Final Gear Oil

    EBU00705 Final gear oil Final gear oil measurement 1. Place the machine on a level place. 2. Remove the oil filler bolt and check the oil level. It should be up to the brim of the hole. If the level is low, add oil to raise it to the proper level.
  • Page 117 2. Place the machine on a level place. 6. Fill the final gear case with oil. 3. Place a container under the final gear Recommended oil: case. SAE 80 API “GL-4” Hypoid gear oil 4. Remove the oil filler bolt and the drain Oil quantity: bolt to drain the oil.
  • Page 118: Spark Plug Inspection

    Do not attempt to diagnose such prob- lems yourself. Instead, take the machine to a Yamaha dealer. You should periodically remove and inspect the spark plug because heat a. Spark plug gap...
  • Page 119: Air Filter Cleaning

    EBU00589* Air filter cleaning NOTE: There is a check hose at the bottom of the air filter case. If dust or water collects in this hose, empty the hose and clean the air filter element and air filter case. 1. Air cleaner case cover 3.
  • Page 120 4. Separate the foam cover from the air WARNING filter element. POTENTIAL HAZARD 5. Tap the element lightly to remove Using low flash point solvents or gaso- most of the dust and dirt. Blow out the line to clean the foam cover. remaining dirt with compressed air as WHAT CAN HAPPEN shown.
  • Page 121 NOTE: CAUTION: The air filter element should be cleaned ev- ● Do not twist the foam filter when ery 20 ~ 40 hours. It should be cleaned squeezing it. more often if the machine is operated in Do not add oil to the foam filter. ●...
  • Page 122: Spark Arrester Cleaning

    EBU00754 Spark arrester cleaning 2. Start the engine and rev it up approxi- Select a well-ventilated area free of com- mately twenty times while momen- bustible materials and make sure the ex- tarily creating exhaust system back haust pipe and muffler are cool. pressure by blocking the end of the 1.
  • Page 123: Carburetor Adjustment

    CAUTION: Could start a fire. The carburetor was set at the Yamaha fac- HOW TO AVOID THE HAZARD tory after many tests. If the settings are When cleaning the spark arrester: disturbed by someone without sufficient...
  • Page 124: Idle Speed Adjustment

    EBU00301 Idle speed adjustment NOTE: A diagnostic tachometer must be used for this procedure. 1. Start the engine and warm it up for a few minutes at approximately 1,000 to 2,000 r/min. Occasionally rev the en- gine to 4,000 to 5,000 r/min. The en- gine is warm when it quickly responds 1.
  • Page 125: Valve Clearance Adjustment

    This adjustment however, should be left to a 1. Loosen the locknut. professional Yamaha service technician. 2. Turn the adjusting bolt until the throt- tle lever free play is 3 ~ 5 mm (0.12 ~ 0.20 in).
  • Page 126: Front Brake Pad Inspection

    Apply the rear brake and check the position of the indicator. If the indicator reaches the wear limit line, ask a Yamaha dealer to re- place shoes as a set. 1. Wear indicator (× 2) a. Wear limit: 1mm (0.04 in) 1.
  • Page 127: Front Brake Fluid Level Inspection

    EBU00315* Front brake fluid level inspection Insufficient brake fluid may let air enter the brake system, possibly causing the brakes to become ineffective. Before riding, check that the brake fluid is above the lower level and replenish when necessary. Observe these precautions: 1.
  • Page 128: Brake Fluid Replacement

    1. Complete fluid replacement should be up spilled fluid immediately. done only by trained Yamaha service 6. Have a Yamaha dealer check the cause personnel. if the brake fluid level goes down. 2. Have a Yamaha dealer replace the fol-...
  • Page 129 Make sure the brakes do not drag. Make sure the brakes are not spongy. ● All air must be bled from the brake system. Replacement of brake components re- quires professional knowledge. These procedures should be performed by a Yamaha dealer. 8-22...
  • Page 130: Rear Brake Pedal And Lever Adjustment

    EBU00329 Rear brake pedal and lever adjustment b. Turn the adjusting nut on the brake 1. Brake pedal free play adjustment rod until free play is 20 ~ 30 mm (0.8 ~ a. Fully loosen the adjusting nut on the 1.18 in).
  • Page 131 2. Brake lever free play adjustment b. Screw in the adjusting nut on brake ca- a. Loosen the locknut and fully turn in ble to provide a gap of 0 ~ 1 mm (0 ~ the adjusting bolt at the brake lever. 0.04 in) between the lever and the pin.
  • Page 132 2. Adjusting bolt ● Make sure the brakes do not drag. a. 5 ~ 7 mm (0.20 ~ 0.28 in) Replacement of brake components d. Tighten the locknut. requires professional knowledge. These procedures should be per- formed by a Yamaha dealer. 8-25...
  • Page 133: Clutch Adjustment

    EBU00346 Clutch adjustment 3. Tighten the locknut to specification. 1. Loosen the locknut. Tightening torque: 2. Slowly turn the adjusting bolt counter- 15 Nm (1.5 m·kg, 11 ft·lb) clockwise until resistance is felt. Then, turn it 1/8 turn clockwise. NOTE: Turn the adjusting bolt counterclockwise to decrease the clutch free play and turn it clockwise to increase the free play.
  • Page 134: Cable Inspection And Lubrication

    Cable inspection and lubrication Lubricate the inner cables and the cable ends. If the cables do not operate smooth- WARNING ly, ask a Yamaha dealer to replace them. POTENTIAL HAZARD Recommended lubricant: Damaged control cables. Yamaha chain and cable lube or...
  • Page 135: Wheel Removal

    EBU00373 EBU00702 Wheel removal Wheel installation 1. Elevate the wheel by placing a suitable When installing the wheel, reverse the re- stand under the frame. moval procedure. 2. Remove the nuts from the wheel. NOTE: 3. Remove the wheel assembly. The arrow mark on the tire must point toward the rotating direction of the wheel.
  • Page 136: Battery

    If the battery seems to have discharged, consult a Yamaha dealer. CAUTION: Do not try to remove the sealing caps of the battery cells. You may damage the battery.
  • Page 137: Battery Maintenance

    EBU00385 Battery maintenance HOW TO AVOID THE HAZARD 1. When the machine is not used for a Avoid contact with skin, eyes or cloth- month or longer, remove the battery ing. Always shield eyes when working and store it in a cool, dark place. Com- near batteries.
  • Page 138: Fuse Replacement

    2. If a fuse is blown, turn off the main switch and install a new fuse of the specified amperage. Then turn on the switches. If the fuse immediately blows again, consult a Yamaha dealer. Specified fuses: 1. Main fuse 2. Spare fuse...
  • Page 139 WARNING POTENTIAL HAZARD Using an improper fuse. WHAT CAN HAPPEN An improper fuse can cause damage to the electrical system which could lead to a fire. HOW TO AVOID THE HAZARD Always use a fuse of the specified rat- ing. Never use a material in place of the proper fuse.
  • Page 140: Replacing The Headlight Bulb

    EBU00753 Replacing the headlight bulb If the headlight bulb burns out, replace the bulb as follows: 1. Remove the headlight assembly by re- moving the screws. 2. Disconnect the coupler. 3. Remove the light unit assembly from the headlight assembly by removing the screw.
  • Page 141 8. Install the headlight assembly and WARNING connect the coupler. POTENTIAL HAZARD 9. Adjust the headlight beam. (See page The headlight bulb is hot when it is on 8-35.) and immediately after it is turned off. WHAT CAN HAPPEN You can be burned, or a fire could start if the bulb touches something flammable.
  • Page 142: Headlight Beam Adjustment

    Troubleshooting Although Yamaha machines receive a rigid CAUTION: inspection before shipment from the facto- It is advisable to have a Yamaha dealer ry, trouble may occur during operation. Any problem in the fuel, compression, or make this adjustment. ignition systems can cause poor starting 1.
  • Page 143 WARNING POTENTIAL HAZARD Checking the fuel system while smok- ing or near an open flame. WHAT CAN HAPPEN Fuel can ignite or explode, causing se- vere injury or property damage. HOW TO AVOID THE HAZARD Do not smoke when checking the fuel system.
  • Page 144: Troubleshooting Chart

    2. Compression There is compression. Compression normal. Use the electric starter to see if there is compression. No compression. Ask a Yamaha dealer to inspect. Wipe clean with 3. Ignition Ignition system dry cloth. Spark good. normal. Remove the plug and check the electrodes.
  • Page 145: Cleaning And Storage

    EBU00419 CLEANING AND STORAGE CAUTION: Excessive water pressure may cause wa- A. CLEANING ter seepage and deterioration of wheel Frequent, thorough cleaning of your ma- bearings, brakes, transmission seals and chine will not only enhance its appearance electrical devices. Many expensive repair but will improve its general performance bills have resulted from improper high and extend the useful life of many compo-...
  • Page 146 6. Clean the seat with a vinyl upholstery WARNING cleaner to keep the cover pliable and POTENTIAL HAZARD glossy. Operation with wet brakes after wash- 7. Automotive type wax may be applied ing. to all painted and chrome plated sur- WHAT CAN HAPPEN faces.
  • Page 147: Storage

    Do not apply NOTE: oil to any rubber parts or the seat cov- Use of fuel stabilizer and conditioner elimi- nates the need to drain the fuel system. Consult a Yamaha dealer if the fuel system needs to be drained instead.
  • Page 148 7. Remove the battery and charge it. Store it in a dry place and recharge it once a month. Do not store the battery in an excessively warm or cold place (less than 0 ˚C (30 ˚F) or more than 30 ˚C (90 ˚F)).
  • Page 149: Specifications

    EBU00428 SPECIFICATIONS MODEL YFM400N Dimension: Overall length 2,007 mm (79.0 in) Overall width 1,125 mm (44.3 in) Overall height 1,172 mm (46.1 in) Seat height 855 mm (33.7 in) Wheel base 1,230 mm (48.4 in) Minimum ground clearance 245 mm (9.65 in) Minimum turning radius 3,000 mm (118.1 in) Basic weight:...
  • Page 150 MODEL YFM400N Engine oil: Type See page 5-7 Quantity: Periodic oil change 2.9 L (2.6 Imp qt, 3.1 US qt) With oil filter replacement 3.0 L (2.6 Imp qt, 3.2 US qt) Total amount 3.5 L (3.1 Imp qt, 3.7 US qt) Final gear oil: Type SAE 80 API “GL-4”...
  • Page 151 MODEL YFM400N Transmission: Primary reduction system Spur gear Primary reduction ratio 76/24 (3.167) Secondary reduction system Shaft drive 28/24 × 24/18 × 33/09 (5.703) Secondary reduction ratio Transmission type Constant mesh 5-speed forward, 1-speed reverse Operation Left foot operation Gear raito: 40/12 (3.333) 34/18 (1.889) 30/22 (1.364)
  • Page 152 MODEL YFM400N Suspension: Front Double wishbone Rear Swingarm (monocross) Shock absorber: Front Coil spring/Oil damper Rear Coil spring/Oil damper Wheel travel: Front wheel travel 150 mm (5.91 in) Rear wheel travel 150 mm (5.91 in) Electrical: Ignition system DC. C.D.I. Generator system A.C.
  • Page 153: Noise Regulation

    EBU00430 NOISE REGULATION TAMPERING WITH NOISE CONTROL SYSTEM PROHIBITED: Federal law prohibits the following acts or the causing thereof: (1) The removal or render- ing inoperative by any person other than for purposes of maintenance, repair, or replace- ment of any device or element of design incorporated into any new vehicle for the purpose of noise control prior to its sale or delivery to the ultimate purchaser or while it is in use or (2) the use of the vehicle after such device or element of design has been removed or ren- dered inoperative by any person.
  • Page 154: Maintenance Record

    EBU00431 MAINTENANCE RECORD Copies of work orders and/or receipts for parts you purchase and install will be required to document maintenance done in accordance with the warranty. The chart below is printed only as a reminder to you that the maintenance work is required. It is not acceptable proof of maintenance work.
  • Page 155 13-1...
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  • Page 158 1414 1414 1414 14-2...
  • Page 159 EBU00436 WARNING Indicates a potential hazard that could result in serious injury or death. 14-3...
  • Page 160 EBU00437 14-5...
  • Page 161 LOCATE AND READ OWNER'S MANUAL. FOLLOW ALL INSTRUCTIONS AND WARNINGS. (For replacement manual, call 1-800-532-1558) YAMAHA MOTOR CO., LTD. PRINTED ON RECYCLED PAPER PRINTED IN USA 2000 · ? - ?.? × 1 CR...

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