2004 YAMAHA AEROX50 check engine light

3
INSTRUMENT AND CONTROL FUNCTIONS
EAU00029
Main switch/steering lock
The main switch/steering lock controls
the ignition and lighting systems, and
is used to lock the steering. The various
positions are described below.
PUSH
OPEN
ZAUM0253
EAU00038
OFF “ ”
All electrical systems are off. The key
can be removed.
EAU04470
CHECK “”
The 2-stroke engine oil level warning
light should come on. See page 3-2 for
an explanation of the engine oil level
warning light.
EAU00040
LOCK “ ”
The steering is locked, and all electrical
systems are off. The key can be
removed.
To lock the steering
1. Turn the handlebars all the way to
the left.
2. Push the key in from the “
”
position, and then turn it to “
”
while still pushing it.
3. Remove the key.
To unlock the steering
Push the key in, and then turn it to “
”
while still pushing it.
EW000016
Never turn the key to “ ” or “ ”
while the scooter is moving, otherwise
the electrical systems will be switched
off, which may result in loss of control
or an accident. Make sure that the scoo-
ter is stopped before turning the key
to “ ” or “ ”.
WARNING
3-1
EAU00037
ON “ ”
All electrical circuits are supplied with
power, and the engine can be started.
The key cannot be removed.
NOTE :
The headlight, meter lighting and
taillight come on automatically when the
engine is started.

INSTRUMENT AND CONTROL FUNCTIONS
3
EAU03034
Indicator and warning lights
TEMP
123
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1. Turn signal indicator light “ ”
2. High beam indicator light “
”
3. Oil indicator light “ ”
EAU00057
Turn signal indicator light “ ”
This indicator light flashes when the
turn signal switch is pushed to the left
or right.
EAU00063
High beam indicator light “ ”
This indicator light comes on when the
high beam of the headlight is switched
on.
EAU02958
Oil level warning light “ ”
This warning light comes on when the
key is in the “
” position or when the
oil level in the 2-stroke engine oil tank
is low during operation. If the warning
light comes on during operation, stop
immediately and fill the oil tank with
Yamalube 2 or equivalent 2-stroke
engine oil of either JASO grade "FC"
or ISO grades "EG-C" or "EG-D". The
warning light should go off after the 2-
stroke engine oil tank has been refilled.
NOTE :
If the warning light does not come on
when the key is in the “
” position or
does not go off after the 2-stroke engine
oil tank has been refilled, have a Yamaha
dealer check the electrical circuit.
EC000000
Do not operate the scooter until you
know that the engine oil level is
sufficient.
CAUTION:
EAU01716
Coolant temperature warning light
“
”
This warning light comes on when the
engine overheats. When this occurs,
stop the engine immediately and allow
the engine to cool.
EC000002
Do not operate the engine if it is
overheated.
CAUTION:
TEMP
1ZAUM0255
1. Coolant temperature warning light “ ”
3-2

OPERATION AND IMPORTANT RIDING POINTS
5
EAU01118
EW000129
•Become thoroughly familiar
with all operating controls and
their functions before riding.
Consult a Yamaha dealer
regarding any control or
function that you do not
thoroughly understand.
•Never start the engine or
operate it in a closed area for
any length of time. Exhaust fu-
mes are poisonous, and
inhaling them can cause loss of
consciousness and death
within a short time. Always
make sure that there is
adequate ventilation.
•For safety, always start the
engine with the centerstand
down.
WARNING
CAUTION:
CAUTION:
PUSH
OPEN
ZAUM0253
5-1
EAU00415*
Starting the engine
1. Turn the key to "", then when the
oil level warning light comes on,
turn it to "
".
EC000045
If the oil level warning light does not
come on, have a Yamaha dealer
check the electrical circuit.
2. Turn the starter (choke) on and
completely close the throttle. (See
page 3-9 for starter (choke)
operation.)3. Start the engine by pushing the
start switch or by pushing the
kickstarter lever down, while
applying the front or rear brake.
NOTE :
If the engine fails to start by pushing
the start switch, release the switch, wait
a few seconds, and then try again. Each
starting attempt should be as short as
possible to preserve the battery. Do not
crank the engine more than 5 seconds
on any one attempt. If the engine does
not start with the starter motor, try using
the kickstarter.
4. After starting the engine, move the
starter (choke) lever back halfway.
ECA00045
For maximum engine life, never
accelerate hard when the engine is
cold!

OPERATION AND IMPORTANT RIDING POINTS
5
EAU00436
Engine break-in
There is never a more important period
in the life of your engine than the period
between 0 and 1,000 km. For this
reason, you should read the following
material carefully.
Since the engine is brand new, do not
put an excessive load on it for the first
1,000 km. The various parts in the
engine wear and polish themselves to
the correct operating clearances.
During this period, prolonged full-
throttle operation or any condition that
might result in engine overheating must
be avoided.
EAUT0003
0 — 150 km
Avoid operation above 1/3 throttle. Stop
the engine and let it cool for 5 to 10
minutes after every hour of operation.
Vary the speed of the scooter from time
to time. Do not operate it at one set
throttle position.150 — 500 km
Avoid prolonged operation above 1/2
throttle.
500 — 1,000 km
Avoid cruising speeds in excess of 3/
4 throttle.
ECAT0001
After 1,000 km of operation, be sure
to replace the final transmission oil.
1,000 km and beyond
Avoid prolonged full throttle operation.
Vary speeds occasionally.
EC000049
If any engine trouble should occur
during the engine break-in period,
immediately have a Yamaha dealer
check the vehicle.
CAUTION:
CAUTION:
5-4
EAU03093
Tips for reducing fuel
consumption
Fuel consumption depends largely on
your riding style. Consider the following
tips to reduce fuel consumption:
•Thoroughly warm up the engine.
•Avoid high engine speeds during
acceleration.
•Avoid high engine speeds with no
load on the engine.
•Turn the engine off instead of
letting it idle for an extended length
of time (e.g., in traffic jams, at
traffic lights or at railroad
crossings).

EAU00462
PERIODIC MAINTENANCE AND MINOR REPAIR
Periodic maintenance and lubrication chart ............ 6-2
Removing and installing cowling and panel ............ 6-5
Cowling A ................................................................ 6-5
Panel A .................................................................... 6-5
Checking the spark plug ......................................... 6-6
Final transmission oil .............................................. 6-7
Coolant .................................................................... 6-8
Cleaning the air filter element ................................. 6-9
Adjusting the carburetor ........................................ 6-10
Adjusting the throttle cable free play ..................... 6-11
Tires ...................................................................... 6-11
Wheels .................................................................. 6-13
Adjusting the front and rear brake lever
free play ................................................................ 6-13
Checking the front and rear brake pads ................ 6-14
Checking the brake fluid level ............................... 6-14
6 Changing the brake fluid ....................................... 6-15
Adjusting the autolube pump ................................ 6-15
Checking and lubricating the cables ..................... 6-16
Lubricating the front and rear brakes levers .......... 6-16
Checking and lubricating the centerstand ............. 6-16
Checking the front fork .......................................... 6-17
Checking the steering ........................................... 6-17
Checking the wheel bearings ................................ 6-18
Battery ................................................................... 6-18
Replacing the fuse ................................................ 6-20
Replacing a headlight bulb .................................... 6-20
Replacing tail/brake light bulb ............................... 6-21
Replacing a turn signal light bulb .......................... 6-22
Troubleshooting ..................................................... 6-22
Troubleshooting chart ............................................ 6-23
Engine overheating ............................................... 6-24

PERIODIC MAINTENANCE AND MINOR REPAIR
6
EAU01651
Checking the spark plug
The spark plug is an important engine
component, which should be checked
periodically, preferably by a Yamaha
dealer. Since heat and deposits will
cause any spark plug to slowly erode,
it should be removed and checked in
accordance with the periodic mainte-
nance and lubrication chart. In addition,
the condition of the spark plug can
reveal the condition of the engine.
The porcelain insulator around the
center electrode of the spark plug
should be a medium-to-light tan (the
ideal color when the scooter is ridden
normally). If the spark plug shows a
distinctly different color, the engine
could be defective. Do not attempt to
diagnose such problems yourself.
Instead, have a Yamaha dealer check
the scooter.
If the spark plug shows signs of
electrode erosion and excessive carbon
or other deposits, it should be replaced.Specified spark plug:
BR8HS (NGK)
Before installing a spark plug, the spark
plug gap should be measured with a
wire thickness gauge and, if necessary,
adjusted to specification.
Spark plug gap:
0.5 — 0.7 mm
Clean the surface of the spark plug
gasket and its mating surface, and then
wipe off any grime from the spark plug
threads.
a
ZAUM0037
a Spark plug gap
Tightening torque:
Spark plug:
20 Nm (2.0 m
•kg)
NOTE :
If 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.
6-6

PERIODIC MAINTENANCE AND MINOR REPAIR
6
EC000080
•If coolant is not available, use
distilled water or soft tap water
instead. Do not use hard water
or salt water since it is harmful
to the engine.
•If water has been used instead
of coolant, replace it with
coolant as soon as possible,
otherwise the engine may not
be sufficiently cooled and the
cooling system will not be
protected against frost and cor-
rosion.
•If water has been added to the
coolant, have a Yamaha dealer
check the antifreeze content of
the coolant as soon as possi-
ble, otherwise the effectiveness
of the coolant will be reduced.
EW000067
Never attempt to remove the radiator
cap when the engine is hot.
CAUTION:
WARNING
EAU01808*
Coolant
To check the coolant level
1. Place the scooter on a level sur-
face and hold it in an upright po-
sition.
NOTE :
•The coolant level must be
checked on a cold engine since
the level varies with engine
temperature.
•Make sure that the scooter is
positioned straight up when
checking the coolant level. A slight
tilt to the side can result in a false
reading.
2. Remove cowling A. (See page
6-5 for cowling removal and ins-
tallation procedures.)3. Check the coolant level in the
coolant reservoir.
NOTE :
The coolant should be between the
minimum and maximum level marks.
4. If the coolant is at or below the
minimum level mark, open the
reservoir cap, add coolant to the
maximum level mark, and then
close the reservoir cap.
Coolant reservoir capacity:
0.25 L

1
ZAUM0274
1. Coolant tank cap
6-8