YAMAHA YFZ450R 2021 Owners Manual

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TIPIf the specified free play cannot be obtained as de-
scribed above or if the clutch does not operate
correctly, have a Yamaha dealer check the internal
clutch mechanism. EBU26867Drive chain slackThe drive chain slack should be checked before
each ride and adjusted if necessary.TIPWhen checking and adjusting the drive chain
slack, there should be no weight on the ATV and
all tires must be touching the ground. To check the drive chain slack1. Park the ATV on a level surface.
2. Move the ATV back and forth to locate the tightest portion of the drive chain, and then
measure the drive chain slack as shown. 3. If the drive chain slack is incorrect, adjust it as
follows.
To adjust the drive chain slack 1. Park the ATV on a level surface.
2. Loosen the rear wheel axle pinch bolts.
3. Insert a rod of a diameter of 8 mm (0.3 in) and a length of 10 cm (4 in) into one of the holes in
the drive chain tensioner as shown.
Drive chain slack: 25.0–35.0 mm (0.98–1.38 in)
1. Drive chain slack
1
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TIPA rod can be obtained at a Yamaha dealer to make
this adjustment. 4. Shift the transmission into neutral.
5. To tighten the drive chain, push the ATVbackward. To loosen the drive chain, push
the ATV forward. NOTICE: Improper drive
chain slack will overload the engine as well
as other vital parts of the ATV and can lead
to drive chain slippage or breakage. To prevent this from occurring, keep the drive
chain slack within the specified limits.
[ECB00543]
6. Pull the rod out, and then tighten the rear axle
pinch bolts to the specified torque in the or-
der shown.
1. Rear wheel axle pinch bolt
2. Rod
3. Drive chain tensioner
4. Hole
3
4
2 11
Tightening torque:
Rear axle pinch bolt:21 N·m (2.1 kgf·m, 15 lb·ft)
3 1 2
4
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EBU24886Lubricating the drive chainThe drive chain must be cleaned and lubricated at
the intervals specified in the periodic maintenance
chart, otherwise it will quickly wear out, especially
when riding in dusty or wet areas. Service the
drive chain as follows.NOTICEECB00562The drive chain must be lubricated after wash-
ing the ATV or riding in the rain or wet areas.
1. Clean the drive chain with a drive chain clean-er and a small soft brush. NOTICE: To pre-
vent damaging the O-rings, do not clean
the drive chain with steam cleaners, high-
pressure washers or inappropriate sol-
vents.
[ECB00572]
2. Wipe the drive chain dry.
3. Thoroughly lubricate the drive chain with a special O-ring chain lubricant. NOTICE: Do
not use engine oil or any other lubricants
for the drive chain, as they may contain
substances that could damage the O-
rings.
[ECB00582]
EBU24905
Checking and lubricating the cablesThe operation and the condition of all control ca-
bles should be checked before each ride, and the
cables and cable ends should be lubricated if nec-
essary. If a cable is damaged or does not move
smoothly, have a Yamaha dealer check or replace
it.
1. O-rings
1
1
Recommended lubricant:
Yamaha cable lubricant or other suitable cable lubricant
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WARNING
EWB02582Inspect cables frequently and replace if
damaged. Corrosion can result when the ca-
ble sheaths become damaged, and cables
can also become frayed or kinked, which
could restrict the operation of controls and
lead to an accident or injury.
 Always make sure all control cables work
smoothly before you begin riding in cold
weather. If the control cables are frozen or
do not work smoothly, you could be unable
to control the ATV, which could lead to an
accident or collision. EBU24923Checking and lubricating the brake
and clutch leversThe operation of the brake and clutch levers
should be checked before each ride, and the lever
pivots should be lubricated if necessary. Brake lever
Recommended lubricants:
Brake lever:Silicone grease
Clutch lever: Lithium-soap-based greaseUBKD60E0.book Page 39 Wednesday, November 18, 2020 8:39 AM

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Clutch lever
EBUM0171Checking the shift pedalThe operation of the shift pedal should be
checked before each ride. If operation is not
smooth, have a Yamaha dealer check the vehicle.EBU28872Checking and lubricating the brake
pedalThe operation of the brake pedal should be
checked before each ride, and the pedal pivot
should be lubricated if necessary.
EBU38880Checking the wheel hub bearingsThe front wheel hub bearings must be checked at
the intervals specified in the periodic maintenance
chart. If there is play in a wheel hub or if a wheel
does not turn smoothly, have a Yamaha dealer
check the wheel hub bearings.Recommended lubricant:
Lithium-soap-based grease
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EBU24998Lubricating the swingarm pivots
The swingarm pivots must be lubricated by a
Yamaha dealer at the intervals specified in the pe- riodic maintenance chart.EBU25036Lubricating the upper and lower arm
pivotsThe upper and lower arm pivots must be lubricat-
ed at the intervals specified in the periodic main-
tenance chart.Recommended lubricant: Lithium-soap-based grease
Recommended lubricant: Lithium-soap-based grease
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Left side Right side
TIPFor parts equipped with a grease nipple, use a
grease gun. EBU25096Lubricating the steering shaftThe steering shaft must be lubricated by a
Yamaha dealer at the intervals specified in the pe- riodic maintenance chart.
1. Upper grease nipple
2. Lower grease nipple
21
2
1. Upper grease nipple
2. Lower grease nippleRecommended lubricant: Lithium-soap-based grease
1
2
2
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TIPFor parts equipped with a grease nipple, use a
grease gun. EBU2918BBatteryThis model is equipped with a 12-volt VRLA
(valve-regulated 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 tightened, and the bat-
tery terminals cleaned if corroded. If the battery
seems to have discharged, recharge it as soon as
possible.TIPWear gloves and eye protection in a ventilated
area away from sparks and open flames. Wash
hands after handling.
 It is recommended to have the battery serviced
by a Yamaha dealer.
WARNING
EWB02161Battery electrolyte is poisonous and danger-
ous, as it contains sulfuric acid, which can
cause 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. To remove the battery
1. Remove the seat. (See page 5-10.)
2. Remove the battery holding plate by remov- ing the bolts.
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3. 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.
NOTICEECB00622Never attempt to open the battery or remove
the battery cell seals, as this would permanent-
ly damage the battery. To charge the battery
 Confirm the recommended charging rate as
specified on the battery itself.
 Select a suitable charger and follow the manu-
facturer’s instructions.NOTICEECB00933To charge a VRLA (valve-regulated lead-acid)
battery, a special battery charger is required.
Using a conventional battery charger will dam-
age 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.
1. Bolt
2. Battery holding plate
3. Negative battery lead (black)
4. Positive battery lead (red)
1
1
2
3
4
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NOTICEECB00942Always keep the battery charged. Storing the
battery in a discharged state for an extended
period of time will cause permanent battery
damage.
 Do not store the battery in an excessively
cold or warm place [below freezing or above
30 °C (90 °F)]. To install the battery
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]
3. Install the battery holding plate by installing the bolts.
4. Install the seat. (See page 5-10.)TIP Make sure the positive and negative battery
leads are installed as shown.
 Fully charge the battery before installing it. 1. Positive battery lead (red)
2. Negative battery lead (black)
2
1
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