torque YAMAHA YFZ450R 2021 Owners Manual

5-13
5
4. Tighten the locknut to the specified torque. NOTICE: Always tighten the locknut
against the adjusting nut, and then tighten
it to the specified torque.
[ECB00082]
Rebound damping force
Turn the rebound damping force adjusting screw
in direction (a) to increase the rebound damping
force. Turn in direction (b) to decrease the re-
bound damping force.
Spring preload setting:
Minimum (soft):Distance A = 302.5 mm (11.91 in)
Standard: Distance A = 293.0 mm (11.54 in)
Maximum (hard): Distance A = 282.5 mm (11.12 in)
1. Distance A
1
Tightening torque: Locknut:50 N·m (5.0 kgf·m, 37 lb·ft)1. Rebound damping force adjusting screw
(a)
(b)
1
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5-19
5
TIPThe spring preload setting is determined by
measuring distance A, shown in the illustration.
 The shorter distance A is, the greater the spring
preload. The longer distance A is, the lesser the
spring preload.
 Each complete turn of the adjusting nut chang-
es distance A by 1.5 mm (0.06 in).
11. Tighten the locknut to the specified torque.
NOTICE: Always tighten the locknut
against the adjusting nut, and then tighten
it to the specified torque.
[ECB00082]
1. Locknut
2. Spring preload adjusting nut
3. Special wrench
2 13
(a)
(b)
Spring preload setting: Minimum (soft):Distance A = 286.5 mm (11.28 in)
Standard: Distance A = 278.0 mm (10.94 in)
Maximum (hard): Distance A = 266.5 mm (10.49 in)1. Distance A
1
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5-20
512. Connect the air intake duct to the throttle
body, and then tighten the clamp screw at the
throttle body side. NOTICE: Make sure that
the air intake duct is properly connected to
the throttle body, and that the clamp
screw is tightened securely.
[ECB00962]
13. Connect the coupler.
14. Connect the air filter case to the air intake duct, place the air filter case in the original po-
sition, and then tighten the clamp screw at
the air filter case side. NOTICE: Make sure
that the air intake duct is properly con-
nected to the air filter case, and that the
clamp screw is tightened securely.
[ECB00972]
15. Install the air filter case bolts, and then tighten them to the specified torque. 16. Install the air filter case holding plate by in-
stalling the bolts and collars, and then tighten
the bolts to the specified torque.
17. Install the blow-by gas chamber by installing the bolt, tighten the bolt to the specified
torque, and then install the clip to the hose
holder.
18. Install the cowling.
Rebound damping force
Turn the rebound damping force adjusting screw
in direction (a) to increase the rebound damping
force. Turn in direction (b) to decrease the re-
bound damping force.
Tightening torque:
Locknut:30 N·m (3.0 kgf·m, 22 lb·ft)
Tightening torque: Air filter case bolt:7 N·m (0.7 kgf·m, 5.2 lb·ft)
Tightening torque:Air filter case holding plate bolt:7 N·m (0.7 kgf·m, 5.2 lb·ft)
Tightening torque: Blow-by gas chamber bolt:7 N·m (0.7 kgf·m, 5.2 lb·ft)
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9-2
9
EBU29573Owner’s Manual and tool kitBe sure to always keep the Owner’s Manual, the
tool kit and the low-pressure tire gauge with the
vehicle. Make sure to protect the Owner’s Manual
by putting it in the plastic bag, then by placing the
bag in the document pouch.
The information included in this manual and the
tools provided in the tool kit are intended to assist
you in the performance of preventive maintenanceand minor repairs. However, additional tools such
as a torque wrench are necessary to perform cer-
tain maintenance work correctly.
TIPIf you do not have the tools or experience required
for a particular job, have a Yamaha dealer perform
it for you.
1. Owner’s Manual
2. Low-pressure tire gauge
3. Tool kit
1
2
3
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9-14
9
Before installing the spark plug, the spark plug
gap should be measured with a wire thickness
gauge and, if necessary, adjusted to specification.
Clean the surface of the spark plug gasket and its
mating surface, and then wipe off any grime from
the spark plug threads.
TIPIf a torque wrench is not available when installing
the spark plug, a good estimate of the correct
torque is 1/4–1/2 turn past finger tight. However,
the spark plug should be tightened to the speci-
fied torque as soon as possible. EBU2949EEngine oil and oil filter elementThe engine oil level should be checked before
each ride. In addition, the oil must be changed and
the oil filter element replaced at the intervals spec-
ified in the periodic maintenance chart.
To check the engine oil level
1. Park the ATV on a level surface.
2. Start the engine, warm it up until the engine oil has reached a normal temperature of 60
°C (140 °F), let it continue to idle for ten sec-
onds or more, and then turn the engine off.
Specified spark plug:
NGK/CR8E
1. Spark plug gapSpark plug gap:0.7–0.8 mm (0.028–0.031 in)
Tightening torque:Spark plug:13 N·m (1.3 kgf·m, 9.6 lb·ft)
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9-18
9
8. Remove the oil filter element and the O-rings.
9. Install a new oil filter element and new O-
rings.
TIPMake sure that the O-rings are properly seated. 10. Install the oil filter element cover by installing the bolts, and then tighten them to the speci-
fied torque.
1. Oil filter element cover
2. Bolt
1
2
1. Oil filter element
2. O-ringTightening torque:Oil filter element cover bolt:10 N·m (1.0 kgf·m, 7.4 lb·ft)
1
2
2
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9-19
911. Install the crankcase engine oil drain bolt, the
engine oil tank drain bolt and their new gas-
ket, and then tighten the bolts to their speci-
fied torques.
12. Refill with the specified amount of the recom- mended engine oil through the engine oil tank
filler hole.
TIPBe sure to wipe off spilled oil on any parts after the
engine and exhaust system have cooled down.
NOTICEECB00301In order to prevent clutch slippage (since the
engine oil also lubricates the clutch), do not
mix any chemical additives. Do not use oils
with a diesel specification of “CD” or oils of
a higher quality than specified. In addition,
do not use oils labeled “ENERGY CONSERV-
ING II” or higher.
 Make sure that no foreign material enters the
crankcase. 13. Check the engine oil tank filler cap O-ring for
damage, and replace it if necessary.
14. Install and tighten the engine oil tank filler cap.
15. Start the engine, and then let it idle for several minutes while checking it for oil leakage. If oil
is leaking, immediately turn the engine off and
check for the cause.
16. Turn the engine off, and then check the oil level and correct it if necessary.
17. Install the engine guard by installing the bolts, and then tighten them to the specified torque.
NOTICE: Be sure to apply LOCTITE
® to the
engine guard bolts before installing them.
[ECB00372]
Tightening torques: Crankcase engine oil drain bolt:20 N·m (2.0 kgf·m, 15 lb·ft)
Engine oil tank drain bolt: 20 N·m (2.0 kgf·m, 15 lb·ft)
Recommended oil: See page 11-1.
Oil quantity: Without oil filter element replacement:1.40 L (1.48 US qt, 1.23 Imp.qt)
With oil filter element replacement: 1.45 L (1.53 US qt, 1.28 Imp.qt)
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9
EBU38620Why YamalubeYAMALUBE oil is a Genuine YAMAHA Part born ofthe engineers’ passion and belief that engine oil is
an important liquid engine component. We form
teams of specialists in the fields of mechanical en-
gineering, chemistry, electronics and track test-
ing, and have them develop the engine together
with the oil it will use. Yamalube oils take full ad-
vantage of the base oil’s qualities and blend in the
ideal balance of additives to make sure the final oil
clears our performance standards. Thus,
Yamalube mineral, semisynthetic and synthetic oils have their own distinct characters and value.
Yamaha’s experience gained over many years of research and development into oil since the
1960’s helps make Yamalube the best choice for
your Yamaha engine.
EBU23473CoolantThe coolant level should be checked regularly. In
addition, the coolant must be changed at the in-
tervals specified in the periodic maintenance
chart.
Tightening torque:
Engine guard bolt:7 N·m (0.7 kgf·m, 5.2 lb·ft)Recommended coolant:YAMALUBE coolant
Coolant quantity: Coolant reservoir (up to full level):0.25 L (0.26 US qt, 0.22 Imp.qt)
Radiator (including all routes): 1.25 L (1.32 US qt, 1.10 Imp.qt)
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9-27
93. Tap the tailpipe lightly, and then use a wire
brush to remove any carbon deposits from
the spark arrester portion of the tailpipe and
inside of the tailpipe housing. 4. Install the gasket, tailpipe, and retainer and
align the bolt holes.
5. Install the bolts and tighten them to the spec- ified torque.
6. Install the tailpipe cover and align the bolt holes.
7. Install the bolts and tighten them to the spec- ified torque.
1. Bolt
2. Retainer
3. Tailpipe
4. Gasket1
2
3
4
1
1. Tailpipe
2. Spark arresterTightening torque:Retainer bolt:10 N·m (1.0 kgf·m, 7.4 lb·ft)
1
2
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9
EBU29705Adjusting the throttle lever free playPeriodically check the throttle lever free play and
adjust if necessary.1. Slide the rubber cover back.
2. Loosen the locknut.
3. To increase the throttle lever free play, turn
the throttle lever free play adjusting bolt in di-
rection (a). To decrease the throttle lever free
play, turn the adjusting bolt in direction (b).
4. Tighten the locknut.
5. Slide the rubber cover to its original position.
EBU24062Valve clearanceThe valve clearance changes with use, resulting in
improper air-fuel mixture and/or engine noise. To
prevent this from occurring, the valve clearance
must be adjusted by a Yamaha dealer at the inter-
vals specified in the periodic maintenance chart.EBU29602BrakesReplacement of brake components requires pro-
fessional knowledge. Brake service should be
performed by a Yamaha dealer.
Tightening torque:
Tailpipe cover bolt:8 N·m (0.8 kgf·m, 5.9 lb·ft)
1. Rubber cover
2. Throttle lever free play adjusting bolt
3. Locknut
4. Throttle lever free playThrottle lever free play: 2.0–4.0 mm (0.08–0.16 in)
32
4
(a)(b)
1
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