engine YAMAHA NMAX 155 2021 Owner's Manual

Operation and important rid ing points
8-1
8
EAU15952
Read the Owner’s Manual carefully to
become familiar with all controls. If
there is a control or function you do not
understand, ask your Yamaha dealer.
WARNING
EWA10272
Failure to familiarize yourself with
the controls can lead to loss of con-
trol, which coul d cause an acci dent
or injury.
EAU16842
En gine break-inThere is never a more important period
in the life of your engine than the period
between 0 and 1600 km (1000 mi). For
this reason, you should read the fol-
lowing material carefully.
Since the engine is brand new, do not
put an excessive load on it for the first
1600 km (1000 mi). The various parts in
the engine wear and polish themselves
to the correct operating clearances.
During this period, prolonged full-throt-
tle operation or any condition that
might result in engine overheating
must be avoided.
EAUM2012
0–1000 km (0–600 mi)
Avoid prolonged operation above 1/3
throttle. NOTICE: After 1000 km (600
mi) of operation, be sure to replace
the en gine oil an d final transmission
oil.
[ECA11662]
1000–1600 km (600–1000 mi)
Avoid prolonged operation above 1/2
throttle. 1600 km (1000 mi) an
d b eyon d
The vehicle can now be operated nor-
mally.
NOTICE
ECA10271
If any en gine trou ble shoul d occur
d urin g the en gine break-in perio d,
imme diately have a Yamaha dealer
check the vehicle.
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Operation and important ri din g points
8-2
8
EAU86741
Startin g the en gineThe ignition circuit cut-off system will
enable starting only when the side-
stand is up.
To start the engine1. Turn the main switch on.
2. Confirm the indicator and warning light(s) come on for a few sec-
onds, and then go off. (See page
6-1.)TIPDo not start the engine if the en-
gine trouble warning light remains
on.
 The ABS warning light should
come on and stay on until the ve-
hicle reaches a speed of 10 km/h
(6 mi/h).NOTICE
ECA24110
If a warnin g or in dicator li ght does
not work as d escribed a bove, have a
Yamaha dealer check the vehicle.3. Close the throttle completely.
4. While applying the front or rear
brake, push the start switch. 5. Release the start switch when the
engine starts, or after 5 seconds.
Wait 10 seconds before pressing
the switch again to allow battery
voltage to restore.
NOTICE
ECA11043
For maximum en gine life, never ac-
celerate har d when the en gine is
col d!
EAU45093
Startin g off1. While pulling the rear brake lever
with your left hand and holding the
grab bar with your right hand,
push the scooter off the center-
stand.
2. Sit astride the seat, and then ad- just the rear view mirrors.
3. Switch the turn signals on.
4. Check for oncoming traffic, and then slowly turn the throttle grip
(on the right) in order to take off.
5. Switch the turn signals off.1. Grab bar
1
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Operation and important rid ing points
8-3
8
EAU16782
Acceleration an d d ecelerationThe speed can be adjusted by opening
and closing the throttle. To increase
the speed, turn the throttle grip in di-
rection (a). To reduce the speed, turn
the throttle grip in direction (b).
EAU60650
Brakin g
WARNING
EWA17790
Avoi d b rakin g har d or su ddenly
(especially when leanin g over to
one si de), otherwise the vehicle
may skid or overturn.
 Railroa d crossin gs, streetcar
rails, iron plates on road con-
struction sites, an d manhole
covers become extremely slip-
pery when wet. Therefore, slow
d own when approachin g such
areas an d cross them with cau-
tion.
 Keep in min d that b raking on a
wet road is much more difficult.
 Ride slowly d own a hill, as brak-
in g d ownhill can be very d iffi-
cult.1. Close the throttle completely.
2. Apply both front and rear brakes simultaneously while gradually in-
creasing the pressure.
EAU16821
Tips for re ducin g fuel con-
sumptionFuel consumption depends largely on
your riding style. Consider the follow-
ing tips to reduce fuel consumption:
 Avoid high engine speeds during
acceleration.
 Avoid high engine speeds with no
load on the engine.
 Turn the engine off instead of let-
ting it idle for an extended length
of time (e.g., in traffic jams, at traf-
fic lights or at railroad crossings).
(b)
(a)
ZAUM0199
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Operation and important ri din g points
8-4
8
EAUW4891
Parkin g When parking, turn off the Stop and
Start System and then stop the engine.
After turning off the main switch, be
sure to turn off the smart key and take
it with you.
WARNING
EWA18840
 Since the en gine an d exhaust
system can b ecome very hot,
park in a place where pe destri-
ans or chil dren are not likely to
touch them an d b e burne d.
 Do not park on a slope or on soft
groun d, otherwise the vehicle
may overturn, increasin g the
risk of a fuel leak an d fire.
 Do not park near grass or other
flamma ble materials which
mi ght catch fire.
 If the Stop an d Start System is
left turne d on, the b attery could
b ecome dischar ged an d it may
not be possi ble to restart the
en gine due to insufficient b at-
tery volta ge.
TIPEven when the vehicle is parked in a lo-
cation partitioned by a fence or the
glass window of a shop, if the smart
key is within operating range, other
people will be able to start the engine
and operate the vehicle. Please turn
the smart key off when leaving the ve-
hicle. (See page 3-8.)
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Periodic maintenance an d a djustment
9-2
9
EAU71021
TIP The annual checks must be performe d every year, except if a distance- based maintenance is performe d in-
stea d.
 From 30000 km (17500 mi), repeat the maintenance intervals starting from 6000 km (3500 mi).
 Items marked with an asterisk should be performed by a Yamaha dealer as they require special tools, data and tech-
nical skills.
EAU71041
Perio dic maintenance chart for the emission control systemNO. ITEM CHECK OR MAINTENANCE JOB ODOMETER READING
ANNUAL
CHECK
1000 km
(600 mi) 6000 km
(3500 mi) 12000 km
(7000 mi) 18000 km
(10500 mi) 24000 km
(14000 mi)
1 *Fuel line • Check fuel hoses for cracks or
damage.
• Replace if necessary. 
2 Spark plu g• Check condition.
• Adjust gap and clean.

•Replace. 
3 *Valve clearance • Check and adjust. 
4 *Fuel injection • Check engine idle speed. 
5 *Exhaust system • Check for leakage.
• Tighten if necessary.
• Replace gasket if necessary. 
6 *Evaporative emis-
sion control system • Check control system for dam-
age.
• Replace if necessary. 
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Periodic maintenance an d a djustment
9-5
9
20 En gine oil • Change (warm engine before
draining).
• Check oil level and vehicle for oil leakage. At the initial interval and when the oil change indicator flashes or
comes on. 
21 *Engine oil strainer • Clean. 
22 *Final transmission
oil • Check vehicle for oil leakage.

• Change. 
23 *Coolin g system • Check coolant level and vehicle
for coolant leakage. 
• Change. Every 3 years
24 *V-belt • Replace. When the V-belt replacement indicator flashes or comes on
25 *Front an
d rear
b rake switches • Check operation.

26 *Movin
g parts an d
cab les • Lubricate.

27 *Throttle
grip hous-
in g an d cab le • Check operation and free play.
• Adjust the throttle cable free play
if necessary.
• Lubricate the throttle grip housing and cable. 
28 *Li
ghts, si gnals an d
switches • Check operation.
• Adjust headlight beam.

NO. ITEM CHECK OR MAINTENANCE JOB
ODOMETER READING
ANNUAL
CHECK
1000 km
(600 mi) 6000 km
(3500 mi) 12000 km
(7000 mi) 1
8000 km

(10500 mi) 24000 km
(14000 mi)
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Periodic maintenance an d a djustment
9-6
9
EAU72790
TIP Engine air filter and V-belt air filter
• This model’s engine air filter is equipped with a disposable oil-coated paper element, which must not be cleaned with compressed air to avoid damaging it.
• The engine air filter element needs to be replaced and the V-belt air filter element needs to be serviced more fre-
quently when riding in unusually wet or dusty areas.
 Hydraulic brake service
• After disassembling the brake master cylinders and calipers, always change the fluid. Regularly check the brake fluid levels and fill the reservoirs as required.
• Every two years replace the internal components of the brake master cylinders and calipers, and change the brake fluid.
• Replace the brake hoses every four years and if cracked or damaged.
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Periodic maintenance an d a djustment
9-9
9 2. Install the windshield by installing
the screws.
EAU67161
Checkin g the spark plu gThe spark plug is an important engine
component, which is easy to check.
Since heat and deposits will cause any
spark plug to slowly erode, the spark
plug should be removed and checked
in accordance with the periodic main-
tenance and lubrication chart. In addi-
tion, the condition of the spark plug
can reveal the condition of the engine.
To remove the spark plu g
1. Place the vehicle on the center- stand.
2. Remove panels A and B. (See page 9-7.)
3. Remove the spark plug cap. 4. Remove the spark plug as shown,
with the spark plug wrench includ-
ed in the owner’s tool kit.
To check the spark plu g
1. Check that the porcelain insulator around the center electrode of the
spark plug is a medium-to-light
tan (the ideal color when the vehi-
cle is ridden normally).
TIPIf the spark plug shows a distinctly dif-
ferent color, the engine could be oper-
ating improperly. Do not attempt to
diagnose such problems yourself. In-
stead, have a Yamaha dealer check
the vehicle.
1. Spark plug cap
1
1. Spark plug wrench
1
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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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