Page 1 READ THIS MANUAL CAREFULLY! It contains important safety information. OWNER’S MANUAL YFM400S WARNING This ATV should not be ridden by anyone under 16 years of age. LIT-11626-17-08 5GW-F8199-14...
Page 2 EBU00776...
Page 3 Yamaha experience in the production of fine sporting, touring, and pace-setting racing ATVs. 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
EBU00801 I MPORTANT 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 notations: The Safety Alert Symbol means ATTENTION! BECOME ALERT! YOUR SAFETY IS INVOLVED! Failure to follow WARNING instructions could result in severe WARNING...
Page 5 Please check your local riding laws and regulations before operating this machine. EBU01067 YFM400S OWNER’S MANUAL ©2003 by Yamaha Motor Corporation, AFFIX DEALER U.S.A. 1st edition, April 2003 LABEL HERE All rights reserved. Any reprinting or...
Page 6: Table Of Contents
EBU00014 CONTROL FUNCTIONS....4-1 WARNING Main switch ........4-1 Indicates a potential hazard that could Indicator and warning lights .....4-2 result in serious injury or death. Speedometer ........4-4 Fuel gauge ........4-4 Handlebar switches ......4-5 CONTENTS Throttle lever ........4-6 Speed limiter ........4-7 Front brake lever......4-8 LOCATION OF THE WARNING Brake pedal and rear brake lever ..4-8 AND SPECIFICATION LABELS..
Page 7 Rear shock absorber OPERATION ........6-1 adjustment........4-18 Starting a cold engine...... 6-1 Auxiliary DC jack......4-19 Starting a warm engine ....6-3 Warming up ........6-3 PRE-OPERATION CHECKS ... 5-1 Reverse knob operation and Front and rear brakes ..... 5-3 reverse driving .......
Page 8 Crossing through shallow water..7-34 Brake fluid replacement ....8-23 Riding over rough terrain....7-36 Front brake lever free play.....8-24 Sliding and skidding ...... 7-38 Brake pedal and rear brake lever What to do if ........7-40 adjustment ........8-25 What to do ........7-40 Adjusting the rear brake light switch ...........8-28 PERIODIC MAINTENANCE AND...
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 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. WARNING Overloading this ATV or carrying cargo improperly can change handling. stability and braking performance and can lead to an accident.
Page 12 WARNING Overloading this ATV or carrying cargo improperly can change handling. stability and braking performance and can lead to an accident. Never exceed the maximum rear cargo limit of : 80kg (176 lbs) NEVER sit on the carrier. Refer to instructions in the Owner's Manual.
Page 13 MAXIMUM . LOADING LIMIT MAXIMUM LOADING LIMIT ( 4 1 0 k g f ) PULLING LOAD: 4020 N 904 l b f ( 1 5 k g f ) TONGUE WEIGHT: 147 N 33 l b f 5FU-F151K-00...
Page 14: Safety Information
EBU00924 SAFETY INFORMATION AN ATV IS NOT A TOY AND CAN BE HAZARDOUS TO OPERATE. An ATV handles differently 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 obstacles, if you fail to take proper precautions.
Page 15 Always avoid operating an ATV on any paved surfaces, including sidewalks, driveways, park- ing 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 properly. You should also wear eye protection (goggles or face shield), gloves, boots, long-sleeved shirt or jacket, and long pants.
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 excessive 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 stall- ing, use proper gear and maintain a steady speed when climbing a hill. If you stall or roll back- wards, follow the special procedure for braking described in this manual. Dismount on the uphill side or to a side if pointed straight uphill.
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 distributed and securely attached.
Page 19 WARNING When transporting the ATV in another vehicle, be sure it is kept upright and POTENTIAL HAZARD that the fuel cock is in the “OFF” posi- Improper handling of gasoline. tion. Otherwise, fuel may leak out of the WHAT CAN HAPPEN 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 ATV in an area with adequate ventilation.
Page 21: Description And Machine Identification
EBU00032 DESCRIPTION AND MACHINE IDENTIFICATION 1. Spark arrester 13. Front wheel 2. Rear carrier 14. Rear brake lever 3. Seat 15. Parking brake lock plate 4. Auxiliary DC jack 16. Starter (choke) 5. Front carrier 17. Speedometer 6. Brake pedal 18.
Page 22: Identification Number Records
This number can be used for ordering a new when ordering spare parts from a Yamaha key. dealer or for reference in case the vehicle is stolen.
Page 23: Vehicle Identification Number
Record the information on this la- bel 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 to 1.
Page 24: Control Functions
EBU00039 CONTROL FUNCTIONS WARNING Indicates a potential hazard that could result in serious injury or death. EBU00942 Main switch Functions of the respective switch positions are as follows: The engine can be started only at this position and the headlights and taillight come on when the light switch is on.
Page 25: Indicator And Warning Lights
EBU00802 EBU00732 Indicator and warning lights Oil temperature warning light “OIL TEMP” When the oil temperature reaches a specified level, this light comes on to warn that the en- gine oil temperature is too hot. If the warning light comes on during operation, stop the en- gine 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 and Ask a Yamaha dealer to electrical circuit are OK. Go inspect the electrical circuit. ahead with riding.
Page 27: Speedometer
EBU00051 EBU00052 Speedometer Fuel gauge The speedometer shows riding speed. This The fuel gauge indicates the amount of fuel in speedometer is equipped with an odometer the fuel tank. When the needle reaches the and trip odometer. The trip odometer can be red line, refill the tank at the first opportunity.
Page 28: Handlebar Switches
EBU00053 EBU00607 Handlebar switches Start switch “ ” The starter motor cranks the engine when this switch is pushed. CAUTION: See starting instructions prior to starting the engine. (See page 6-1 for details.) EBU01204 Light switch “ /OFF” Set the switch to “ ”...
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 1. Throttle lever ATV. Consult a Yamaha dealer if you can’t find or solve the problem yourself.
Page 30: Speed Limiter
EBU01159 Speed limiter WARNING The speed limiter keeps the throttle from fully POTENTIAL HAZARD opening, even when the throttle lever is Improper adjustment of the speed limit- pushed to the maximum. Turning in the ad- er and throttle. justing screw limits the maximum engine pow- WHAT CAN HAPPEN er available and decreases the maximum 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 ap- ply the front brake. 1. Brake pedal 1. Front brake lever EBU00732 Brake pedal and rear brake lever The brake pedal is located on the right side of the ATV and the rear brake lever is located on the left handlebar.
Page 32: Parking Brake
EBU00074 Parking brake WARNING Use the parking brake when you have to start POTENTIAL HAZARD the engine or park the machine, especially on Improper use of the parking brake. a slope. Apply the rear brake lever and push WHAT CAN HAPPEN down the lock plate to apply the parking The ATV could start moving unexpect- brake.
Page 33: Shift Pedal
EBU00084 EBU10280 Shift pedal Reverse knob “REV” This machine is equipped with a constant- The reverse knob is used to shift into reverse mesh 5-speed forward and 1-speed reverse gear. Refer to the “Reverse knob operation transmission. The shift pedal is located on the and reverse driving”...
Page 34: Recoil Starter
EBU00590 Recoil starter WARNING Firmly grasp the handle and pull slightly until POTENTIAL HAZARD engagement can be felt. Then pull forcefully, Starting the engine in gear and/or start- being careful not to pull the rope all the way ing the engine without setting the park- out.
Page 35: Fuel Tank Cap
EBU00092 Fuel tank cap Remove the fuel tank cap by turning it coun- terclockwise. 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. ON: With the lever in this position, fuel flows to the carburetor.
Page 37: Starter (Choke)
EBU00095 Starter (choke) “ ” Starting a cold engine requires a richer air-fuel mixture. A separate starter circuit supplies this mixture. Move in direction a to turn on the starter (choke). Move in direction b to turn off the starter (choke).
Page 38: Seat
EBU00567 Seat To install the seat, insert the projections on To remove the seat, pull the seat lock lever the front of the seat into the seat holders and upward and pull up the seat at the rear. push down on the seat at the rear. NOTE: Make sure that the seat is securely fitted.
Page 39: Storage Box
EBU00581 EBU00582 Storage box Front carrier Maximum load limit: 2.0 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
Uneven adjustment can cause poor A special wrench can be obtained at a handling and loss of stability, which Yamaha dealer to make this adjustment. could lead to an accident. HOW TO AVOID THE HAZARD Always adjust the shock absorbers on the left and right side to the same set- ting.
Page 41: Rear Shock Absorber Adjustment
To decrease the spring preload, turn the ad- justing ring in direction b. NOTE: A special wrench can be obtained at a Yamaha dealer to make this adjustment. 1. Spring preload adjusting ring 2. Position indicator 4-18...
Page 42: Auxiliary Dc Jack
EBU01002 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, radios, etc. The auxiliary DC jack should only be used when the engine is running. 1.
Page 43 CAUTION: Do not use accessories requiring more than the above maximum capac- ity. This may overload the circuit and cause the fuse to blow. If accessories are used without the engine running or with the headlights 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 • Fill with DOT 4 brake fluid if necessary. 5-3–5-4, 8-21–8-28 • Check operation, condition and free play. 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
Brake operation should be a firm feeling when the brake is Test the brakes at slow speed after starting applied. If not, have a Yamaha dealer in- out to make sure they are working properly. If spect them. the brakes do not provide proper braking per-...
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 a Yamaha dealer check for the cause.
Page 48: Fuel
EBU01085 Fuel Your Yamaha engine has been designed to Make sure there is sufficient gasoline in the use regular unleaded gasoline with a pump tank. octane number ([R+M]/2) of 86 or higher, or research octane number of 91 or higher. If...
Page 49 Fuel can spill, which can cause a fire hol containing methanol is not recommended and severe injury. by Yamaha because it may cause fuel system Fuel expands when it heats up. If the damage or vehicle performance problems. fuel tank is overfilled, fuel could spill out due to heat from the engine or the sun.
Page 50: Engine Oil
EBU10842 EBU00493 Engine oil Final gear oil Make sure the engine oil is at the specified Make sure the final gear oil is at the specified level. Add oil as necessary. (See page 8-5.) level. Add oil as necessary. (See pages 8-10– 8-12 for details.) CAUTION: Recommended oil:...
Page 51: Throttle Lever
Fittings and fasteners Yamaha dealer repair as necessary for proper Always check the tightness of chassis fittings operation. and fasteners before a ride. Take the machine to a Yamaha dealer or refer to the Service Manual for correct tightening torque.
Page 52: Tires
HOW TO AVOID THE HAZARD lodge from the rim under severe 1. The tires listed below have been ap- riding conditions. proved by Yamaha Motor Co., Ltd. for this model. Other tire combinations The following are minimums: are not recommended.
Page 53 4. Use no more than the following pres- sures when seating the tire beads. Front 250 kPa (2.5 kgf/cm , 36 psi) Rear 250 kPa (2.5 kgf/cm , 36 psi) Higher pressures may cause the tire to burst. Inflate the tires very slowly and carefully.
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 second reading. Dust or dirt in the gauge could cause the first reading to be incorrect.
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. Tire wear limit 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 en- understand, ask your Yamaha dealer. gine stop switch to “ ”. 4. Shift the transmission into neutral.
Page 57 25 °C (80 °F) and warm engine the light does not come on, ask a start position. Yamaha dealer to inspect it. The engine can be started in any gear if the rear brake lever is applied. However, it is recommended to shift into neutral be- fore 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 the engine for the first time. again. Pause a few seconds before the next attempt. Each cranking should be as short as possible to preserve battery en- EBU00180 ergy.
Page 59: Reverse Knob Operation And Reverse Driving
If the light does not come on, ask CAUTION: 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
EBU12951 Shifting This model has a 5-speed forward and 1-speed reverse transmission with centrifugal automatic clutch. The transmission allows you to control the amount of power you have avail- able at a given speed or for starting, acceler- ating, climbing hills, etc. To shift into neutral, return the throttle lever to the closed position and repeatedly depress the shift pedal until it stops.
Page 61: To Start Out And Accelerate
EBU00205 To start out and accelerate: WARNING 1. Release the throttle lever. POTENTIAL HAZARD Opening the throttle before releasing CAUTION: the shift pedal. Always close the throttle while shifting WHAT CAN HAPPEN gears. Otherwise, damage to the engine The machine could wheelie. This would and drive train may result.
Page 62: To Decelerate
EBU00207 EBU02092 To decelerate: Engine break-in When slowing down or stopping, release the There is never a more important period in the throttle and apply the brakes smoothly and life of your machine than the period between evenly. As you slow down, shift to a lower zero and 20 hours.
Page 63 If any abnormality is noticed during this peri- After break-in: od, consult a Yamaha dealer. Avoid prolonged full throttle operation. Vary speeds occasionally. 0–10 hours: Avoid continuous operation above half throt- tle.
Page 64: Parking
EBU00211 EBU01296 Parking Parking on a slope When parking, stop the engine and shift into WARNING neutral. Turn the fuel cock to “OFF” and apply POTENTIAL HAZARD the parking brake. Parking on a hill or other incline. WHAT CAN HAPPEN The ATV could roll out of control, in- creasing the chance of an accident.
Page 65 1. Bring the ATV to a stop by applying the brakes in low gear. 2. Stop the engine. 3. With the rear brake lever and pedal ap- plied, apply the parking brake and slowly release the brake pedal. 6-10...
Page 66: Accessories And Loading
Choose only accessories designed for your dlebars which could make steering difficult, ATV. Your Yamaha dealer has a variety of an accessory that limits your ability to move genuine Yamaha accessories. Other ac-...
Page 67 EBU00588 Loading Do not exceed the maximum tongue Cargo or a trailer can change the stability and weight. You can measure tongue weight handling of an ATV. with a bathroom scale. Put the tongue of You must use common sense and good judg- the loaded trailer on the scale with the ment when carrying cargo or towing a trailer.
Page 68 Ride more slowly than you would without a WARNING load. The more weight you carry, the slow- POTENTIAL HAZARD er you should go. Although conditions vary, Overloading this ATV or carrying or tow- it is good practice not to exceed 2nd gear ing cargo improperly.
Page 69: Riding Your Atv
Riding Your...
Page 71: Getting To Know Your Atv
WARNING Indicates a potential hazard that could result in serious injury or death. GETTING TO KNOW YOUR ATV begin to ride, be sure you have read this Own- This ATV is mainly for utility use, but may also er’s Manual completely and understand the be used for recreation.
Page 72: Ride With Care And Good Judgement
JUDGEMENT Beginning and inexperienced operators should complete the certified training Get training if you are inexperienced. course offered by Yamaha. They should Beginners should get training from a certified then regularly practice the skills learned instructor. in the course and the operating tech- Become familiar with this ATV at slow speeds niques described in this Owner’s Manu-...
Page 73 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 74 This ATV 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 accident, resulting in harm to you and/ or your passenger.
Page 75 Apparel Operating without protective clothing WARNING increases your chances of severe injury 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 76 Do not operate after consuming alcohol or WARNING drugs. POTENTIAL HAZARD Operator’s performance capability is reduced Operating this ATV after consuming al- 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 77 Pre-operation checks WARNING Always perform the pre-operation checks list- POTENTIAL HAZARD ed on page 5-1 before riding for safety and Operating this ATV with improper tires, proper care of the ATV. or with improper or uneven tire pres- WARNING sure. POTENTIAL HAZARD WHAT CAN HAPPEN Failure to inspect the ATV before oper-...
Page 78 Speed limiter WARNING For riders less experienced with this model, Indicates a potential hazard that could this model is equipped with a speed limiter in result in serious injury or death. the throttle lever housing. The speed limiter keeps the throttle from fully opening, even Do not operate at speeds too fast for your when the throttle lever is pushed to the maxi- skills or the conditions.
Page 79 Loading and accessories WARNING Use extra caution when riding the ATV with POTENTIAL HAZARD additional loads, such as accessories or car- Overloading this ATV or carrying or tow- go. The ATV’s handling may be adversely af- ing cargo improperly. fected. Reduce your speed when adding WHAT CAN HAPPEN additional loads.
Page 80 During operation WARNING Always keep your feet on the footboards dur- POTENTIAL HAZARD ing operation. Otherwise your feet may con- Removing hands from handlebars or tact 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 81 Avoid wheelies and jumping. You may lose control of the ATV 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 82 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 83 Exhaust system The exhaust system on the ATV is very hot during and following operation. To prevent burns, avoid touching the exhaust system. Park the ATV in a place where pedestrians or children are not likely to touch it. WARNING POTENTIAL HAZARD Hot exhaust system.
Page 84: Be Careful Where You Ride
BE CAREFUL WHERE YOU RIDE This ATV 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 85 Do not ride on any public road, street, or high- way. Riding on public roads can result in collisions 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 86 Know the terrain where you ride. Ride cau- tiously in unfamiliar areas. Stay alert for holes, rocks, or roots in the terrain, and oth- er hidden hazards which may cause the ATV to upset. WARNING POTENTIAL HAZARD Failure to use extra care when operating this ATV on unfamiliar terrain.
Page 87 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 88 When riding in an area where you might not WHAT CAN HAPPEN easily be seen, such as desert terrain, mount You could be in a collision. You could a caution flag on the ATV. DO NOT use the be injured. flag pole bracket as a trailer hitch.
Page 89 Select a large, flat area off-road to become fa- With the engine idling, lift the shift pedal to the miliar with your ATV. Make sure that this area 1st gear position and then release the parking is free of obstacles and other riders. You brake.
Page 90 CAUTION: WARNING 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 The wheels could stop rotating.
Page 91: Turning Your Atv
TURNING YOUR ATV HOW TO AVOID THE HAZARD To achieve maximum traction while riding off- Always follow proper procedures for road, the two rear wheels are mounted solidly turning as described in this Owner’s on one axle and turn together at the same Manual.
Page 92 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, incorrect body movements, or too much speed for the sharpness of the turn may cause the ATV to tip.
Page 93: Climbing Uphill
CLIMBING UPHILL HOW TO AVOID THE HAZARD Use proper riding techniques to avoid vehicle Never operate the ATV on hills too steep overturns on hills. Be sure that you can ma- for the ATV or for your abilities. neuver your ATV well on flat ground before at- Practice on smaller hills before attempt- tempting any incline and then practice riding ing large hills.
Page 94 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 95 If you are climbing a hill and you find that you When crossing the side of a hill: have not properly judged your ability to make Always follow proper procedures as de- it to the top, you should turn the ATV around scribed in the Owner’s Manual.
Page 96 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 front Stalling, rolling backwards or improper- wheels which could cause you to lose control. ly dismounting while climbing a hill.
Page 97 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 98: Riding Downhill
RIDING DOWNHILL WARNING When riding your ATV downhill, shift your POTENTIAL HAZARD weight as far to the rear and uphill side of the Going down a hill improperly. ATV as possible. Move back on the seat and WHAT CAN HAPPEN sit with your arms straight.
Page 99 7-31...
Page 100: Crossing A Slope
CROSSING A SLOPE If your ATV does begin to tip over, gradually Traversing a sloping surface on your ATV re- steer in the downhill direction if there are no quires you to properly position your weight to obstacles in your path. As you regain proper maintain proper balance.
Page 101 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 102: Crossing Through Shallow Water
CROSSING THROUGH SHALLOW WATER Remember that wet brakes may have re- The ATV can be used to cross slow moving, duced stopping ability. Test your brakes shallow water of up to a maximum of 35 cm after leaving water. If necessary, apply (14 in) in depth.
Page 103 Test your brakes after leaving the water. Do CAUTION: not continue to ride your ATV without verifying After riding your ATV in water, be sure to that you have regained proper braking ability. drain the trapped water by removing the check hose at the bottom of the air filter case.
Page 104: Riding Over Rough Terrain
RIDING OVER ROUGH TERRAIN WARNING Riding over rough terrain should be done with POTENTIAL HAZARD caution. Look out for obstacles which could Improperly operating over obstacles. cause damage to the ATV or could lead to an WHAT CAN HAPPEN upset or accident. Be sure to keep your feet Could cause loss of control or a colli- firmly mounted on the footboards at all times.
Page 105 7-37...
Page 106: Sliding And Skidding
SLIDING AND SKIDDING If the rear wheels of your ATV start to slide Care should be used when riding on loose or sideways, control can usually be regained (if slippery surfaces since the ATV may slide. If there is room to do so) by steering in the direc- unexpected and uncorrected, sliding could tion of the slide.
Page 107 With practice, over a period of time, skill at WARNING controlled sliding can be developed. The ter- POTENTIAL HAZARD rain should be chosen carefully before at- Skidding or sliding improperly. tempting such maneuvers, since both stability WHAT CAN HAPPEN and control are reduced. Bear in mind that You may lose control of this ATV.
Page 108: 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 have guide only. Be sure to read each section on the room. riding techniques completely.
Page 109 If your ATV is traversing a sloping surface: Be sure to ride with your weight positioned towards the uphill side of the ATV to main- tain proper balance. If the ATV starts to tip, steer down the hill (if there are no obstacles in your way) to regain balance.
Page 110: 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 lubrica- tion will keep your machine in the safest and most efficient condition possible. Safety is an EBU01299 obligation of the machine owner.
Page 111 If during a service operation requiring one, take you have questions, consult an autho- your machine to a Yamaha dealer to check rized Yamaha ATV dealer. the torque settings and adjust them as neces- sary.
Page 112: 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 element •...
Page 113 • Check operation. Lights and switches* • Adjust headlight beams. * Items marked with an asterisk should be performed by a Yamaha dealer as they require special tools, data and technical skills. NOTE: Recommended brake fluid: DOT 4 Brake fluid replacement: •...
Page 114: Engine Oil And Oil Filter Element
EBU11812 Engine oil and oil filter element The engine oil level should be checked before each ride. In addition, the oil must be changed and the oil filter element cleaned at the inter- vals specified in the periodic maintenance and lubrication chart. To check the engine oil level 1.
Page 115 6. Insert the dipstick into the oil filler hole, To change the engine oil (with or without oil filter element cleaning) and then tighten the engine oil filler cap. 1. Place the ATV on a level surface. 2. Warm up the engine for several minutes, and then turn it off.
Page 116 5. Remove the oil filter cover by removing the bolts, and then remove the oil filter el- ement. 1. Engine oil drain bolt 2. O-ring 3. Compression spring 4. Engine oil strainer 1. Engine oil filter cover 2. Engine oil filter cover bolt (× 3) 6.
Page 117 9. Install the oil filter cover by installing the bolts, and then tighten them to the speci- fied torque. Tightening torque: Oil filter cover bolt: 10 Nm (1.0 m·kgf, 7.2 ft·lbf) 10. Install the oil strainer, compression spring, O-ring and engine oil drain bolt. Tighten the engine oil drain bolt to the 1.
Page 118 12. Start the engine, and then let it idle for Recommended oil: several minutes while checking it for oil See page 10-2. leakage. If oil is leaking, immediately turn Oil quantity: the engine off and check for the cause. Without oil filter element replacement: 13.
Page 119: Final Gear Oil
EBU01145 Final gear oil Final gear oil measurement 1. Place the machine on a level surface. 2. Remove the oil filler bolt, and then check the oil level in the final gear case. NOTE: The oil level should be at the brim of the filler hole.
Page 120 Final gear oil replacement 2. Place the machine on a level surface. 1. Remove the final gear case cover by re- 3. Place a container under the final gear moving the bolts. case to collect the used oil. 4. Remove the oil filler bolt and the drain bolt to drain the oil.
Page 121: Spark Plug Inspection
Do not attempt to diagnose such problems Be sure no foreign material enters the final yourself. gear case. Instead, take the ATV to a Yamaha dealer. You should periodically remove and inspect 7. Install the oil filler bolt. the spark plug because heat and deposits will 8.
Page 122: Air Filter Element Cleaning
EBU01301 Before installing the spark plug, measure the Air filter element cleaning electrode gap with a wire thickness gauge NOTE: and adjust it to specification. There is a check hose at the bottom of the air filter case. If dust or water collects in this Spark plug gap: hose, empty the hose and clean the air filter 0.6–0.7 mm (0.024–0.028 in)
Page 123 4. Remove the foam cover from the air filter element. 1. Air filter case cover 2. Holder (× 3) 3. Pull the air filter element out. 1. Air filter element 2. Foam cover 1. Air filter element 8-14...
Page 124 5. Tap the element lightly to remove most of WARNING the dust and dirt. Blow out the remaining POTENTIAL HAZARD dirt with compressed air as shown. If the Using low flash point solvents or gaso- air filter element is damaged, replace it. line to clean the foam cover.
Page 125 10. Install the air filter element. CAUTION: 11. Install the air filter case cover by fasten- Never operate the engine with the air filter ing the holders. element removed. This will allow unfiltered 12. Install the seat. air to enter, causing rapid engine wear and NOTE: possible engine damage.
Page 126: Spark Arrester Cleaning
EBU00754 Spark arrester cleaning 2. Start the engine and rev it up approxi- Select a well-ventilated area free of combusti- mately twenty times while momentarily ble materials and make sure the exhaust pipe creating exhaust system back pressure and muffler are cool. by blocking the end of the muffler with a 1.
Page 127: Carburetor Adjustment
The carburetor is a vital part of the engine and POTENTIAL HAZARD requires very sophisticated adjustment. Most Improperly purging the exhaust system. adjusting should be left to a Yamaha dealer Hot exhaust system. who has the professional knowledge and ex- WHAT CAN HAPPEN perience to do so.
Page 128: Idle Speed Adjustment
EBU01302 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 engine to 4,000 to 5,000 r/min. The engine is warm when it quickly responds to the 1.
Page 129: Valve Clearance Adjustment
This adjust- ment however, should be left to a professional 1. Loosen the locknut. Yamaha service technician. 2. Turn the adjusting bolt until the throttle le- ver free play is 3–5 mm (0.12–0.20 in). 3. Tighten the locknut.
Page 130: Front Brake Pad Check
A wear indicator is provided on the rear brake. If the brake pad thickness is less than 1 mm This indicator allows checking of brake shoe (0.04 in), have a Yamaha dealer replace the wear without disassembling the brake. pads as a set.
Page 131: Brake Fluid Level Check
EBU01304 Brake fluid level check 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 minimum level mark and replenish if necessary. A low brake fluid level may indi- cate worn brake pads and/or brake system leakage.
Page 132: Brake Fluid Replacement
Complete fluid replacement should be done fluid immediately. only by trained Yamaha service personnel. Have a Yamaha dealer check the cause if Have a Yamaha dealer replace the following the brake fluid level goes down. components during periodic maintenance or when they are damaged or leaking.
Page 133: Front Brake Lever Free Play
The front brake lever should have a free play POTENTIAL HAZARD of zero mm (zero in) at the lever end. If not, Operating with improperly serviced or have a Yamaha dealer check the brake sys- adjusted brakes. tem. WHAT CAN HAPPEN You could lose braking ability, which could lead to an accident.
Page 134: Brake Pedal And Rear Brake Lever
EBU13052 Brake pedal and rear brake lever 2. Turn the adjusting nut on the brake rod adjustment until the free play is 20–30 mm (0.79– Brake pedal free play adjustment 1.2 in). 1. Fully loosen the adjusting nut on the brake cable.
Page 135 Brake lever free play adjustment 2. Turn in the adjusting nut on brake cable 1. Loosen the locknut and fully turn in the to provide a gap of 0–1 mm (0–0.04 in) adjusting bolt at the brake lever. between the camshaft lever and the pin. 1.
Page 136 Make sure the brakes do not drag. 1. Locknut 2. Adjusting bolt a. Rear brake lever free play Replacement of brake components re- 4. Tighten the locknut. quires professional knowledge. These procedures should be performed by a Yamaha dealer. 8-27...
Page 137: Adjusting The Rear Brake Light Switch
EBU00834 EBU00346 Adjusting the rear brake light switch Clutch adjustment The rear brake light switch, which is activated 1. Loosen the locknut. by the brake pedal and brake levers, is prop- 2. Slowly turn the adjusting bolt counter- erly adjusted when the brake light comes on clockwise until resistance is felt.
Page 138: Cable Inspection And Lubrication
EBU00356 3. Tighten the locknut to specification. Cable inspection and lubrication WARNING Tightening torque: 20 Nm (2.0 m·kgf, 15 ft·lbf) POTENTIAL HAZARD Damaged control cables. NOTE: WHAT CAN HAPPEN Turn the adjusting bolt counterclockwise to Corrosion can result when the outer decrease the clutch free play and turn it clock- covering of control cables becomes wise to increase the free play.
Page 139: Brake And Shift Pedal/Brake Lever Lubrication
2. Elevate the ATV and place a suitable stand under the frame. Recommended lubricant: 3. Remove the nuts from the wheel. Yamaha chain and cable lube or 4. Remove the wheel. SAE 10W30 motor oil EBU00727 Brake and shift pedal/brake lever...
Page 140: Wheel Installation
EBU01121 Wheel installation 2. Lower the ATV so that the wheel is on the 1. Install the wheel and the nuts. ground. NOTE: Tapered nuts are used for both the front and rear wheels. Install the nut with its ta- pered side towards the wheel.
Page 141: Battery
Keep out of reach of chil- tery. If the battery seems to have discharged, dren. consult a Yamaha dealer. Antidote: EXTERNAL: Flush with water. CAUTION: INTERNAL: Drink large quantities of wa- Do not try to remove the sealing caps of ter or milk.
Page 142: Battery Maintenance
Then turn on the switches. If CAUTION: the fuse immediately blows again, con- A special battery charger (constant volt- sult a Yamaha dealer. age/ampere or constant voltage) is re- Specified fuses: quired recharging...
Page 143 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- 1. Main fuse 2.
Page 144: Replacing A Headlight Bulb
EBU13061 Replacing a headlight bulb 3. Remove the headlight unit from the If a headlight bulb burns out, replace the bulb headlight assembly by removing the as follows. screws. 1. Remove the headlight assembly by re- moving the screws. 2. Disconnect the headlight coupler. 1.
Page 145 4. Remove the headlight bulb holder cover. WARNING 5. Push the headlight bulb holder inward, POTENTIAL HAZARD turn it counterclockwise, and then re- A headlight bulb is hot when it is on and move the defective bulb. immediately after it is turned off. WHAT CAN HAPPEN You can be burned, or a fire could start if the bulb touches something flamma-...
Page 146 7. Install the headlight bulb holder cover. CAUTION: Make sure the headlight bulb holder cover is securely fitted over the bulb holder and seated against the reflector. 8. Place the headlight unit in the original po- sition, and then install the screws. 9.
Page 147: Headlight Beam Adjustment
Tail/brake light bulb replacement 1. Open the storage box. (See page 4-16.) CAUTION: 2. Remove the nuts together with the wash- It is advisable to have a Yamaha dealer ers. make this adjustment. To raise the beam, turn the adjusting screw in direction a.
Page 148 1. Tail/brake light bulb holder 1. Tail/brake light bulb holder 2. Bulb 4. Remove the defective bulb from the bulb 5. Install a new bulb in the bulb holder by holder by pushing it inward and turning it pushing it inward and turning it clockwise. counterclockwise.
Page 149: Troubleshooting
EBU00412 Troubleshooting WARNING Although Yamaha machines receive a rigid in- POTENTIAL HAZARD spection before shipment from the factory, Checking the fuel system while smok- trouble may occur during operation. Any prob- ing or near an open flame. lem in the fuel, compression, or ignition sys-...
Page 150: Troubleshooting Chart
No fuel. 2. Compression There is compression. Compression normal. Use the electric starter to see if there is compression. Ask a Yamaha dealer to No compression. inspect. 3. Ignition Wipe clean with dry cloth. Ignition system is Spark is good.
Page 151: 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 machine bearings, brakes, transmission seals and will not only enhance its appearance but will electrical devices. Many expensive repair improve its general performance and extend bills have resulted from improper high the useful life of many components.
Page 152 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 to ing. all painted and chrome plated surfaces. WHAT CAN HAPPEN Avoid combination cleaner-waxes.
Page 153: Storage
Do not apply oil to fuel) any rubber parts or the seat cover. NOTE: Use of fuel stabilizer and conditioner elimi- nates the need to drain the fuel system. Con- sult a Yamaha dealer if the fuel system needs to be drained instead.
Page 154 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 ex- cessively warm or cold place (less than 0 °C (30 °F) or more than 30 °C (90 °F)). NOTE: Make any necessary repairs before storing the machine.
Page 155: Specifications
EBU00428 SPECIFICATIONS MODEL YFM400 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) Ground clearance 245 mm ( 9.65 in) Minimum turning radius...
Page 156 MODEL YFM400 Engine oil: Type 0˚ 90˚ 110˚ 130˚F 10˚ 30˚ 50˚ 70˚ YAMALUBE 4 (20W40) or SAE 20W40 YAMALUBE 4 (10W30) or SAE 10W30 SAE 5W30 -20˚ -10˚ 0˚ 20˚ 30˚ 40˚ 50˚C 10˚ Recommended engine oil classification API Service SE, SF, SG or higher CAUTION: In order to prevent clutch slippage (since the en- gine oil also lubricates the clutch), do not mix any...
Page 157 MODEL YFM400 Final gear oil: Type SAE 80 API “GL-4” Hypoid gear oil Quantity Periodic oil change 0.23 L (0.20 lmp qt, 0.24 US qt) Air filter: Dry type element Fuel: Type UNLEADED GASOLINE ONLY Tank capacity 15 L (3.3 Imp gal, 4.0 US gal) Reserve amount 4.0 L (0.9 Imp gal, 1.1 US gal) Carburetor:...
Page 158 MODEL YFM400 Transmission: Primary reduction system Spur gear Primary reduction ratio 76/24 (3.166) 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 (1.363)
Page 159 MODEL YFM400 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 160 MODEL YFM400 Fuses: Main fuse 30 A Headlight fuse 15 A Ignition fuse 10 A Auxiliary DC jack fuse 10 A Carburetor warmer fuse 10 A 10-6...
Page 161: 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 rendering inop- erative by any person other than for purposes of maintenance, repair, or replacement of any de- vice 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 rendered inoperative by any person.
Page 162: Maintenance Record
EBU00431 MAINTENANCE RECORD Copies of work orders and/or receipts for parts you purchase and install will be required to docu- ment maintenance done in accordance with the warranty. The chart below is printed only as a re- minder to you that the maintenance work is required. It is not acceptable proof of maintenance work.
Page 163: Atv Limited Warranty
EBU00432 YAMAHA MOTOR CORPORATION, U.S.A. ATV LIMITED WARRANTY 13-1...
Page 164 13-2...
Page 165: Yamaha Extended Service (Y.e.s.)
EBU00435 YAMAHA EXTENDED SERVICE (Y.E.S.) 14-1...
Page 166 14-2...
Page 167 EBU00436 WARNING Indicates a potential hazard that could result in serious injury or death.
Page 168 EBU00437...
Page 169 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 2003.04-1.3 ×1 CR...

Yamaha BIG BEAR YFM400S Owner's Manual

Quick Links

Troubleshooting

Related Manuals for Yamaha BIG BEAR YFM400S

Summary of Contents for Yamaha BIG BEAR YFM400S

Table of Contents