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PERIODIC MAINTENANCE AND ADJUSTMENT
6-17
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8
9
TIP
The coolant should be between the
minimum and maximum level marks.
5. If the coolant is at or below the
minimum level mark, open the
coolant reservoir cap, add coolant
to the maximum level mark, and
then close the coolant reservoir
cap.
WARNING! Remove only
the coolant reservoir cap. Never
attempt to remove the radiator
cap when the engine is
hot.
[EWA15161]
NOTICE:
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 cool-
ant as soon as possible, other-
wise the cooling system will not
be protected against frost and
corrosion. If water has been
added to the coolant, have a
Yamaha dealer check the anti-
freeze content of the coolant as
soon as possible, otherwise the
effectiveness of the coolant willbe reduced.
[ECA10472]
6. Install the coolant reservoir cover
by installing the screw.
7. Place the right floorboard mat in
the original position.
EAU34206
Air filter elements and check
hoses and V-belt case air filter
element
The air filter elements and the V-belt
case air filter element should be ser-
viced at the intervals specified in the
periodic maintenance and lubrication
chart. Service all air filter elements
more frequently if you are riding in un-
usually wet or dusty areas.
Replacing the air filter elements
1. Place the scooter on the center-
stand.
TIP
Continue as follows for each air filter el-
ement.
2. Remove the air filter case cover by
removing the rubber caps and
screws.
1. Minimum level mark
2. Maximum level mark
3. Coolant reservoir cap
Coolant reservoir capacity (up to the
maximum level mark):
0.32 L (0.34 US qt, 0.28 Imp.qt)
1
2
3
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9Engine overheating
WARNING
EWAT1040
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.
Place a thick rag, like a towel, over the radiator cap, and then slowly rotate the cap counterclockwise to the de-
tent 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.
TIP
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.
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 TIP.)
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.
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Page 87 of 94

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SPECIFICATIONS
EAU2633Z
Dimensions:
Overall length:
2230 mm (87.8 in)
Overall width:
780 mm (30.7 in)
Overall height:
1380 mm (54.3 in)
Seat height:
760 mm (29.9 in)
Wheelbase:
1565 mm (61.6 in)
Ground clearance:
120 mm (4.72 in)
Minimum turning radius:
2600 mm (102.4 in)
Weight:
Curb weight:
YP400 220 kg (485 lb)
YP400A 223 kg (492 lb)
Engine:
Engine type:
Liquid cooled 4-stroke, DOHC
Cylinder arrangement:
Single cylinder
Displacement:
395 cm
3
Bore
×
stroke:
83.0
×
73.0 mm (3.27
×
2.87 in)
Compression ratio:
10.60 :1
Starting system:
Electric starter
Lubrication system:
Wet sump
Engine oil:
Recommended brand:
YAMALUBE
Type:
SAE 10W-30, 10W-40, 10W-50, 15W-40,
20W-40 or 20W-50
Recommended engine oil grade:
API service SG type or higher, JASO stan-
dard MA
Engine oil quantity:
Without oil filter element replacement:
1.50 L (1.59 US qt, 1.32 Imp.qt)
With oil filter element replacement:
1.70 L (1.80 US qt, 1.50 Imp.qt)
Final transmission oil:
Type:
YAMALUBE 10W-40 or SAE 10W-30 type
SE motor oil
Quantity:
0.25 L (0.26 US qt, 0.22 Imp.qt)
Cooling system:
Coolant reservoir capacity (up to the maxi-
mum level mark):
0.32 L (0.34 US qt, 0.28 Imp.qt)
Radiator capacity (including all routes):
1.57 L (1.66 US qt, 1.38 Imp.qt)
Air filter:
Air filter element:
Oil-coated paper element
Fuel:
Recommended fuel:
Regular unleaded gasoline only
Fuel tank capacity:
14.0 L (3.70 US gal, 3.08 Imp.gal)
Fuel injection:
Throttle body:
ID mark:
5RUG 20
Spark plug(s):
Manufacturer/model:
NGK/CR7E
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
Clutch:
Clutch type:
Dry, centrifugal automatic
Transmission:
Primary reduction ratio:
1.000
Final drive:
Gear
Secondary reduction ratio:
6.643 (31/14 x 42/14)
-20 -10 0
10 20 30
40
50 ˚C
SAE 10W-30
SAE 15W-40SAE 20W-40SAE 20W-50
SAE 10W-40SAE 10W-50
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