2017 YAMAHA YFM90 battery

Engine break-in ........................................... 6-4
Parking ........................................................ 6-5
Parking on a slope ...................................... 6-5
Accessories and loading ............................. 6-6
RIDING YOUR ATV ........................................ 7-1 GETTING TO KNOW YOUR ATV ................ 7-2
RIDE WITH CARE AND GOOD JUDGMENT .............................................. 7-2
BE CAREFUL WHERE YOU RIDE ............... 7-9
TURNING YOUR ATV................................ 7-12
CLIMBING UPHILL ................................... 7-13
RIDING DOWNHILL .................................. 7-16
CROSSING A SLOPE................................ 7-17
CROSSING THROUGH SHALLOW WATER .................................................... 7-18
RIDING OVER ROUGH TERRAIN ............. 7-20
SLIDING AND SKIDDING .......................... 7-20
WHAT TO DO IF... ..................................... 7-21
WHAT TO DO... ......................................... 7-22
PERIODIC MAINTENANCE AND
ADJUSTMENT................................................ 8-1 Owner’s manual and tool kit ....................... 8-2
Periodic maintenance chart for the emission control system ........................... 8-3 General maintenance and lubrication
chart.......................................................... 8-5
Checking the spark plug............................. 8-9
Engine oil .................................................. 8-11
Transmission oil ........................................ 8-14
Cleaning the air filter element ................... 8-15
Cleaning the spark arrester ...................... 8-18
Adjusting the carburetor ........................... 8-19
Adjusting the engine idling speed ............ 8-19
Adjusting the throttle lever free play ......... 8-20
Valve clearance......................................... 8-21
Brakes....................................................... 8-21
Checking the front and rear brake shoes ...................................................... 8-21
Adjusting the front brake lever free play... 8-22
Adjusting the rear brake lever free play .... 8-24
Drive chain slack....................................... 8-25
Lubricating the drive chain ....................... 8-27
Checking and lubricating the cables ........ 8-28
Checking and lubricating the front and rear brake levers ..................................... 8-29
Checking the wheel hub bearings ............ 8-29
Lubricating the front knuckle pivots ......... 8-30
Lubricating the steering shaft ................... 8-30
Battery ...................................................... 8-31
Replacing the fuse .................................... 8-33
Removing a wheel .................................... 8-34
UBD361E0.book Page 2 Monday, January 25, 2016 10:53 AM

3-1
3
EBU17681
DESCRIPTION
EBU17691Left view
EBU17701Right view
1. Fuel tank cap
2. Fuel cock
3. Air filter
4. Fuse
5. Battery
6. Rear shock absorber assembly spring preload adjusting ring
7. Kickstarter lever cap
1 2 3 4,5
76
1. Spark arrester
2. Owner’s tool kit
3. Front shock absorber assembly spring preload adjusting ring
4. Spark plug
5. Engine oil filler cap
6. Transmission oil filler cap
12 3
65 4
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4-7
4
EBU33891KickstarterA kickstarter lever is located under the seat. (See
page 4-12.) Use the kickstarter to start the engine
if the battery is discharged.1. Remove the kickstarter lever cap. 2. Install the kickstarter lever.
3. Move the kickstarter lever down lightly with
your foot until the gears engage, and then
push it down smoothly but forcefully.1. Kickstarter lever
1
1. Kickstarter lever cap
1
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4-8
4
NOTICEECB02300Do not use the kickstarter if the battery is not
installed or if the battery leads are not connect-
ed. EBU18721Fuel tank capRemove the fuel tank cap by turning it counter-
clockwise.
EBU18757FuelMake sure there is sufficient gasoline in the tank.
WARNING
EWB02522Gasoline and gasoline vapors are extremely
flammable. To avoid fires and explosions and
to reduce the risk of injury when refueling, fol-
low these instructions. 1. Before refueling, turn off the engine and besure that no one is sitting on the vehicle. Nev-
er refuel while smoking, or while in the vicinity
1. Kickstarter lever
1
1. Fuel tank cap
1
UBD361E0.book Page 8 Monday, January 25, 2016 10:53 AM

6-2
6Ambient temp./starter (choke) position
6. Completely close the throttle lever and start the engine by pushing the start switch.
TIPIf the engine fails to start, release the start
switch, then push it again. Pause a few seconds
before the next attempt. Each cranking should
be as short as possible to preserve battery en-
ergy. Do not crank the engine more than 10 sec-
onds on each attempt. 
If the engine fails to start using the start switch,
try using the kickstarter. (See page 4-7.)
7. If the engine is started with the starter (choke)
in position (1), the starter (choke) should be
returned to position (2) to warm up the en-
gine. If the engine is started with the starter
(choke) in position (2), keep the starter (choke)
in this position to warm up the engine.
8. Continue warming up the engine until it idles smoothly, then return the starter (choke) to
position (3) before riding.TIPThe engine is warm when it responds quickly to
the throttle with the starter (choke) turned off. 9. Release the parking brake.NOTICEECB00164For maximum engine life, never accelerate
hard when the engine is cold!
1. Fully open
2. Half open
3. Closed
4. Starter (choke)
4
3
2
1
(1) (3)
(2)
UBD361E0.book Page 2 Monday, January 25, 2016 10:53 AM

8-31
8
EBU34020BatteryThe battery is located under the seat. (See page
4-12.)
This model is equipped with a VRLA (Valve Regu-
lated Lead Acid) battery. There is no need to
check the electrolyte or to add distilled water.
However, the battery lead connections need to be
checked and, if necessary, tightened.
WARNING
EWB02161Battery electrolyte is poisonous and danger-
ous, as it contains sulfuric acid, which can cau-
se severe burns. Avoid contact with skin, eyes
or clothing. Always shield your eyes when
working near batteries.
Antidote:
EXTERNAL: Flush with water.
INTERNAL: Drink large quantities of water or
milk. Follow with milk of magnesia, beaten egg
or vegetable oil. Call a physician immediately.
EYES: Flush with water for 15 minutes and get
prompt medical attention.
Batteries produce explosive gases. Keep
sparks, flame, cigarettes or other sources of
ignition away. Ventilate when charging or using
in an enclosed space.KEEP OUT OF REACH OF CHILDREN.
NOTICEECB00621Never attempt to remove the battery cell seals,
as this would permanently damage the battery. To remove the battery
1. Remove the seat. (See page 4-12.)
2. Unhook the battery band.1. Positive battery lead (red)
2. Negative battery lead (black)
3. Battery
4. Battery band
3
4
2
1
UBD361E0.book Page 31 Monday, January 25, 2016 10:53 AM

8-32
83. Disconnect the negative battery lead first,
then the positive battery lead by removing
their bolt. NOTICE: When removing the bat-
tery, the main switch must be off, and the
negative lead must be disconnected be-
fore the positive lead.
[ECB01002]
4. Pull the battery out of its compartment.
To charge the battery
Have a Yamaha dealer charge the battery as soon
as possible if it seems to have discharged. Keep
in mind that the battery tends to discharge more
quickly if the ATV is equipped with optional elec-
trical accessories.NOTICEECB00932To charge a VRLA (Valve Regulated Lead Acid)
battery, a special (constant-voltage) battery
charger is required. Using a conventional bat-
tery charger will damage the battery. To store the battery
 If the ATV will not be used for more than one
month, remove the battery, fully charge it, and
then place it in a cool, dry place. 
If the battery will be stored for more than two
months, check it at least once a month and fully
charge it if necessary.
NOTICEECB00941Always keep the battery charged. Storing a
discharged battery can cause permanent bat-
tery damage. To install the batteryTIPBe sure the battery is fully charged. 1. Place the battery in its compartment.
2. Connect the positive battery lead first, then
connect the negative battery lead by installing
their bolt. NOTICE: When installing the bat-
tery, the main switch must be off, and the
positive lead must be connected before
the negative lead.
[ECB01111]
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8-33
8
3. Hook the battery band.
4. Install the seat. (See page 4-12.)
EBU25244Replacing the fuseThe fuse holder is located under the seat. (See
page 4-12.)
If the fuse is blown, replace it as follows.
1. Turn the key to “OFF” and turn off all electrical circuits.NOTICEECB00641To prevent accidental short-circuiting, turn off
the main switch when checking or replacing a
fuse.
1. Positive battery lead (red)
2. Negative battery lead (black)
2
1
1. Fuse
2. Spare fuse
2 1
UBD361E0.book Page 33 Monday, January 25, 2016 10:53 AM