2021 YAMAHA NMAX 155 maintenance

Periodic maintenance an d a djustment
9-10
9
2. Check the spark plug for electrode
erosion and excessive carbon or
other deposits, and replace it if
necessary.
3. Measure the spark plug gap with a wire thickness gauge and, if nec-
essary, adjust the gap to specifi-
cation. To install the spark plu
g
1. Clean the surface of the spark plug gasket and its mating sur-
face, and then wipe off any grime
from the spark plug threads.
2. Install the spark plug with the spark plug wrench, and then tight-
en it to the specified torque.
TIPIf a torque wrench is not available
when installing a 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
specified torque as soon as possible.3. Install the spark plug cap.TIPInstall the spark plug cap so that it is
positioned as shown in the illustration
and the spark plug lead does not con-
tact any surrounding parts.
4. Install the panels.
Specifie d spark plu g:
NGK/CPR8EA-91. Spark plug gapSpark plu g g ap:
0.8–0.9 mm (0.031–0.035 in)
Ti ghtenin g torque:
Spark plug: 13 N·m (1.3 kgf·m, 9.6 lb·ft)
1. Spark plug cap
2. Spark plug lead
1
2
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Periodic maintenance an d a djustment
9-11
9
EAU36113
CanisterThis model is equipped with a canister
to prevent the discharging of fuel vapor
into the atmosphere. Before operating
this vehicle, make sure to check the
following:
 Check each hose connection.
 Check each hose and canister for
cracks or damage. Replace if
damaged.
 Make sure that the canister
breather is not blocked, and if
necessary, clean it.
EAU66995
Engine oil an d oil strainerThe engine oil level should be checked
before each ride. In addition, the oil
must be changed and the oil strainer
cleaned at the intervals specified in the
periodic maintenance and lubrication
chart.
To check the en gine oil level
1. Place the vehicle on the center- stand. A slight tilt to the side can
result in a false reading.
2. Start the engine, warm it up for several minutes, and then turn it
off.
3. Wait a few minutes until the oil set- tles, remove the engine oil filler
cap, wipe the engine oil dipstick
clean, insert it back into the oil fill-
er hole (without screwing it in), and
then remove it again to check the
oil level. WARNING! The muffler
an d muffler protector become
very hot d uring use. To avoi d
possi ble burns, let the muffler
an d protector cool before re-
movin g the oil filler cap.
[EWA17810]
TIPThe engine oil should be between the
tip of the dipstick and the maximum
level mark.4. If the engine oil is not between the
tip of the dipstick and the maxi-
mum level mark, add sufficient oil
of the recommended type to raise
it to the correct level.
5. Insert the dipstick into the oil filler hole, and then tighten the oil filler
cap.
1. Canister
2. Canister breather
2
1
1. Oil filler hole
2. O-ring
3. Engine oil dipstick
4. Maximum level mark
5. Tip of the engine oil dipstick
3245
1
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Periodic maintenance an d a djustment
9-12
9
To chan
ge the en gine oil an d clean
the oil strainer 1. Start the engine, warm it up for several minutes, and then turn it
off.
2. Place an oil pan under the engine to collect the used oil.
3. Remove the engine oil filler cap and engine oil drain bolts A and B
to drain the oil from the crankcase.
NOTICE: When removin g the
en gine oil drain bolt B, the O-
rin g, compression sprin g, an d
oil strainer will fall out. Take
care not to lose these parts.
[ECAT1022]
4. Clean the engine oil strainer with solvent, and then check it for
damage and replace it if neces-
sary.
5. Install the engine oil strainer, com- pression spring, new O-ring and
engine oil drain bolt B.TIPMake sure that the O-ring is properly
seated.
6. Install engine oil drain bolt A andits new gasket, and then tighten
both drain bolts to their specified
torques.
7. Refill with the specified amount of the recommended engine oil, and
then install and tighten the oil filler
cap.TIPBe sure to wipe off spilled oil on any
parts after the engine and exhaust sys-
tem have cooled down.NOTICE
ECA24060
Make sure that no forei gn material
enters the crankcase.
1. Engine oil drain bolt A
2. Gasket
3. Oil strainer
4. Compression spring
5. O-ring
6. Engine oil drain bolt B
2 3
4
5
6
1
Ti ghtenin g torque:
Engine oil drain bolt A: 20 N·m (2.0 kgf·m, 15 lb·ft)
Engine oil drain bolt B:
20 N·m (2.0 kgf·m, 15 lb·ft)
Recommen ded en gine oil:
See page 11-1.
Oil quantity: 0.90 L (0.95 US qt, 0.79 Imp.qt)
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Periodic maintenance an d a djustment
9-13
9 8. 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.
9. Turn the engine off, and then check the oil level and correct it if
necessary.
10. Reset the oil change tripmeter and oil change indicator “OIL”. (See
page 6-8 for reset procedures.)
EAU85450
Why Yamalu beYAMALUBE oil is a Genuine YAMAHA
Part born of the engineers’ passion
and belief that engine oil is an impor-
tant liquid engine component. We form
teams of specialists in the fields of me-
chanical engineering, chemistry, elec-
tronics and track testing, and have
them develop the engine together with
the oil it will use. Yamalube oils take full
advantage of the base oil’s qualities
and blend in the ideal balance of addi-
tives 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 expe-
rience gained over many years of re-
search and development into oil since
the 1960’s helps make Yamalube the
best choice for your Yamaha engine.
EAU67822
Final transmission oilThe final transmission case must be
checked for oil leakage before each
ride. If any leakage is found, have a
Yamaha dealer check and repair your motorcycle. In addition, the final trans-
mission oil must be changed as follows
at the intervals specified in the periodic
maintenance and lubrication chart. 1. Start the engine and warm up the final transmission oil by riding the
motorcycle for several minutes.
2. Stop the engine and then place the motorcycle on the center-
stand.
3. Place an oil pan under the final transmission case to collect the
used oil.
4. Remove the final transmission oil filler cap and its O-ring from the fi-
nal transmission case.
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Periodic maintenance an d a djustment
9-14
9
5. Remove the final transmission oil
drain bolt and its gasket to drain
the oil from the final transmission
case. 6. Install the final transmission oil
drain bolt and its new gasket, and
then tighten the bolt to the speci-
fied torque.
TIPBefore installing the final transmis-
sion oil drain bolt and gasket, ap-
ply oil to them.
 Wipe off any excess oil after-
wards.7. Refill with the specified amount of
the recommended final transmis-
sion oil. WARNING! Make sure
that no forei gn material enters
the final transmission case.
Make sure that no oil gets on
the tire or wheel.
[EWA11312]
8. Install the final transmission oil fill- er cap and its new O-ring, and
then tighten the oil filler cap.
9. Check the final transmission case for oil leakage. If oil is leaking,
check for the cause.
1. Final transmission oil filler cap
2. O-ring
1. Final transmission oil drain bolt
2. Gasket
1
2
12
Ti ghtenin g torque:
Final transmission oil drain bolt:
20 N·m (2.0 kgf·m, 15 lb·ft)
Recommen ded final transmission
oil: See page 11-1.
Oil quantity:
0.10 L (0.11 US qt, 0.09 Imp.qt)
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Periodic maintenance an d a djustment
9-15
9
EAU20071
CoolantThe coolant level should be checked
before each ride. In addition, the cool-
ant must be changed at the intervals
specified in the periodic maintenance
and lubrication chart.
EAUN2930
To check the coolant level
1. Place the vehicle on the center- stand.TIPThe coolant level must be
checked on a cold engine since
the level varies with engine tem-
perature.
 Make sure that the vehicle is posi-
tioned straight up when checking
the coolant level. A slight tilt to the
side can result in a false reading.2. Check the coolant level in the
coolant reservoir.TIPThe coolant should be between the
minimum and maximum level marks.
3. If the coolant is at or below theminimum level mark, remove the
right floorboard mat by pulling it
up.
4. Remove the coolant reservoir cov- er. 5. Remove the coolant reservoir cap,
add coolant to the maximum level
mark, and then install the reservoir
cap. WARNING! Remove only
the coolant reservoir cap. Never
attempt to remove the ra diator
cap when the en gine is hot.
[EWA15162]
NOTICE: If coolant is not
availa ble, use d istilled water or
soft tap water instea d. Do not
use har d water or salt water
since it is harmful to the en gine.
If water has been used instead
of coolant, replace it with cool-
ant as soon as possi ble, other-
wise the coolin g system will not
b e protecte d a gainst frost an d
corrosion. If water has been
1. Maximum level mark
2. Minimum level mark
1. Floorboard mat
1
2
1
1. Coolant reservoir cover
1
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Periodic maintenance an d a djustment
9-16
9
a
dde d to the coolant, have a
Yamaha dealer check the anti-
freeze content of the coolant as
soon as possi ble, otherwise the
effectiveness of the coolant will
b e re duce d.
[ECA10473]
6. Install the coolant reservoir cover.
7. Place the right floorboard mat in
the original position and push it
downward to secure it.
EAU33032
Chan gin g the coolant
The coolant must be changed at the in-
tervals specified in the periodic main-
tenance and lubrication chart. Have a
Yamaha dealer change the coolant.
WARNING! Never attempt to remove
the ra diator cap when the en gine is
hot.
[EWA10382] EAU67174
Air filter an
d V- belt case air fil-
ter elementsThe air filter element should be re-
placed and the V-belt case air filter el-
ement should be cleaned at the
intervals specified in the periodic main-
tenance and lubrication chart. Service
the air filter elements more frequently if
you are riding in unusually wet or dusty
areas. The air filter check hose and V-
belt case air filter check hose must be
frequently checked and cleaned if nec-
essary.
Cleanin g the air filter check hose
1. Coolant reservoir capCoolant reservoir capacity (up to
the maximum level mark):
0.13 L (0.14 US qt, 0.11 Imp.qt)
1
1. Air filter check hose
1
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Periodic maintenance an d a djustment
9-17
9 1. Check the hose on the rear side of
the air filter case for accumulated
dirt or water.
2. If dirt or water is visible, remove the hose from the clamp, clean it,
and then install it.
TIPIf dirt or water was found in the check
hose, be sure to check the air filter ele-
ment for excessive dirt or damage and
replace it if necessary.Replacin g the air filter element
1. Place the vehicle on the center- stand.
2. Remove the air filter case cover by removing the screws. 3. Pull the air filter element out.
4. Insert a new air filter element into
the air filter case. NOTICE: Make
sure that the air filter element is
properly seate d in the air filter
case. The en gine shoul d never
b e operated without the air filter
element installe d, otherwise the
piston(s) an d/or cylin der(s) may
b ecome excessively worn.
[ECA10482]
NOTICE
ECA21220
 The air filter element must be
replace d at the intervals speci-
fie d in the perio dic maintenance
chart. 
The air filter element shoul d b e
replace d more frequently if you
often ri de in the rain or dusty ar-
eas.
 The air filter cannot be cleaned
b y blowin g it with compresse d
air. It must b e replaced.
5. Install the air filter case cover by
installing the screws.
Cleanin g the V- belt case check hose
1. Check the hose on the rear side of the V-belt case for accumulated
dirt or water.
2. If dirt or water is visible, remove the hose from the clamp, clean it,
and then install it.
1. Air filter case cover
2. Screw
2 1
2
2
1. Air filter element
11
1. V-belt case check hose
1
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