2003 YAMAHA AEROX50 cooling

PRE-OPERATION CHECKS
4
EAU03439
Pre-operation check list
ITEM CHECKS PAGE
• Check fuel level in fuel tank.
Fuel• Refuel if necessary. 3-5 — 3-6
• Check fuel line for leakage.
• Check oil level in oil tank.
Two-stroke engine oil• If necessary, add recommended oil to specified level. 3-8, 6-15
• Check vehicle for oil leakage.
Final transmission oil• Check vehicle for oil leakage. 6-7
• Check coolant level in reservoir.
Coolant• If necessary, add recommended coolant to specified level. 6-8
• Check cooling system for leakage.
• Check operation.
• If soft or spongy, have Yamaha dealer bleed hydraulic system.
Front brake• Check fluid level in reservoir. 3-5, 6-13 — 6-15
• If necessary, add recommended brake fluid to specified level.
• Check hydraulic system for leakage.
• Check operation.
• If soft or spongy, have Yamaha dealer bleed hydraulic system.
Rear brake• Check fluid level in reservoir. 3-5, 6-13 — 6-15
• If necessary, add recommended brake fluid to specified level.
• Check hydraulic system for leakage.
The condition of a vehicle is the owner’s responsibility. Vital components can start to deteriorate quickly and unexpectedly,
even if the vehicle remains unused (for example, as a result of exposure to the elements). Any damage, fluid leakage or
loss of tire air pressure could have serious consequences. Therefore, it is very important, in addition to a thorough visual
inspection, to check the following points before each ride.
4-1

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

PERIODIC MAINTENANCE AND MINOR REPAIR
6 Engine overheating
EW000070
•Do not remove the radiator cap when the engine and radiator are hot. Scalding hot fluid and steam may be
blown out under pressure, which could cause serious injury. Be sure to wait until the engine has cooled.
•After removing the radiator cap retaining bolt, place a thick rag, like a towel, over the radiator cap, and then
slowly rotate the cap counterclockwise to the detent to allow any residual pressure to escape. When the hissing
sound has stopped, press down on the cap while turning it counterclockwise, and then remove the cap.
NOTE :
If coolant is not available, tap water can be temporarily used instead, provided that it is changed to the recommended
coolant as soon as possible.
WARNING
Wait until the
engine has cooled.Check the coolant level in the
reservoir and radiator.
The coolant level
is OK.
The coolant level is low.
Check the cooling system
for leakage.
Have a Yamaha dealer checkand repair the cooling system.
Add coolant. (See NOTE.)
Start the engine. If the engine overheats again, have a
Yamaha dealer check and repair the cooling system.
There is
leakage.
There is
no leakage.
6-24

SPECIFICATIONS
8
Specifications
Model YQ50
Dimensions:
Overall length 1.743 mm
Overall width 690 mm
Overall height 1.170 mm
Seat height 828 mm
Wheelbase 1.256 mm
Minimum ground clearance 185 mm
Minimum turning radius 1.800 mm
Basic weight:97 kg
(with oil and full fuel tank)
Engine:
Engine type Liquid cooled, 2 stroke
Cylinder arrangement Single cylinder, horizontal
Displacement 49.2 cc
Bore x stroke 40.0 x 39.2
Compression ratio 7.44:1
Starting system Electric and kick starter
Lubrication systemSeparate lubrication (Autolube)
Engine oil:
Type Yamalube 2
or 2 stroke engine oil
Recommended engine oil Jaso FC
classification or ISO EG-C, EG-D
Capacity 1.3 LFinal transmission oil:
Type SAE 10W30 type SE
Quantity 0.13L
Cooling system capacity:1.2L
(total amount)
Air filter type:Wet type element
Fuel:
Recommended fuel Regular unleaded gasoline
(RON 91 mini)
Fuel tank capacity 7L
Carburetor:
Manufacturer DELL'ORTO
Model/quantity PHBN 12HS x1
Spark plug:
Manufacturer/Model NGK / BR8HS
Spark plug gap 0.5—0.7 mm
Clutch type:Dry, centrifugal automatic
Transmission:
Primary reduction system Helical gear
Primary reduction ratio 52/13 (4.000)
Secondary reduction system Spur gear
Secondary reduction ratio 43/14 (3.071)
Transmission type V-belt automatic
Operation Centrifugal automatic type
8-1