Page 15 of 98
DESCRIPTION
2-2
2
3
4
5
6
7
8
9
EAU10420
Right view
5 123
4
7
6
8
1. Grab bar (page 5-2)
2. Passenger seat (page 3-15)
3. Rider seat (page 3-15)
4. Coolant reservoir (page 6-17)
5. Radiator
6. Centerstand (page 6-29)
7. Air filter element (right) (page 6-19)
8. Shock absorber assembly spring preload adjusting ring (page 3-18)
Page 63 of 98

PERIODIC MAINTENANCE AND MINOR REPAIR
6-19
2
3
4
5
67
8
9 corrosion.
If water has been added to the
coolant, have a Yamaha dealer
check the antifreeze content of
the coolant as soon as possible,
otherwise the effectiveness of
the coolant will be reduced.
WARNING
EWA10380
Never attempt to remove the radiator
cap when the engine is hot.
6. Install the coolant reservoir cover
by installing the screw.
7. Place the right floorboard mat in
the original position.
NOTE:
The radiator fan is automatically
switched on or off according to the
coolant temperature in the radia-
tor.
If the engine overheats, see page
6-40 for further instructions.
EAU34204
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.
NOTE:
Continue as follows for each air filter el-
ement.
2. Remove the air filter case cover by
removing the rubber cap and
screws.
Left
Right
3. Pull the air filter element out.
1. Screw
2. Air filter case cover
3. Rubber cap
1. Screw
2. Air filter case cover
3. Rubber cap
1
21
13
3
1
1
23
Page 78 of 98
PERIODIC MAINTENANCE AND MINOR REPAIR
6-34
1
2
3
4
5
6
7
8
9(for ABS models) (for non-ABS models) (for ABS models)
1. Fuse box
2. ABS motor fuse
3. ABS control unit fuse
4. Hazard fuse
1
2
4 3
1. Ignition fuse
2. Signaling system fuse
3. Headlight fuse
4. Radiator fan fuse
5. Backup fuse (for odometer and clock)
6. Fuel injection system fuse
7. Spare fuse
7
123456
1. Ignition fuse
2. Signaling system fuse
3. Headlight fuse
4. Radiator fan fuse
5. Backup fuse (for odometer and clock)
6. Fuel injection system fuse
7. Spare fuse
7
123456
Page 79 of 98
PERIODIC MAINTENANCE AND MINOR REPAIR
6-35
2
3
4
5
67
8
9
CAUTION:
ECA10640
Do not use a fuse of a higher amper-
age rating than recommended to
avoid causing extensive damage to
the electrical system and possibly a
fire.
3. Turn the key to “ON” and turn on
the electrical circuit in question tocheck if the device operates.
4. If the fuse immediately blows
again, have a Yamaha dealer
check the electrical system.
EAU34240
Replacing a headlight bulb
This model is equipped with quartz bulb
headlights. If a headlight bulb burns
out, have a Yamaha dealer replace it
and, if necessary, adjust the headlight
beam.
Specified fuses:
Main fuse:
40.0 A
Ignition fuse:
10.0 A
Signaling system fuse:
10.0 A
Headlight fuse:
25.0 A
Hazard fuse:
10.0 A
Radiator fan fuse:
10.0 A
Fuel injection system fuse:
10.0 A
ABS control unit fuse:
YP400A 10.0 A
ABS motor fuse:
YP400A 30.0 A
Backup fuse:
10.0 A
Page 85 of 98

PERIODIC MAINTENANCE AND MINOR REPAIR
6-41
2
3
4
5
67
8
9 Engine 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.
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.
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.
Page 90 of 98

8-1
1
2
3
4
5
6
7
8
9
SPECIFICATIONS
EAU2633M
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:
With oil and fuel:
YP400 219.0 kg (483 lb)
YP400A 223.0 kg (492 lb)
Engine:
Engine type:
Liquid cooled 4-stroke, DOHC
Cylinder arrangement:
Forward-inclined single cylinder
Displacement:
395.0 cm
3
Bore
×
stroke:
83.0
×
73.0 mm (3.27
×
2.87 in)
Compression ratio:
10.60 :1Starting system:
Electric starter
Lubrication system:
Wet sump
Engine oil:
Type:
SAE 10W-30, SAE 10W-40, SAE 15W-40,
SAE 20W-40 or SAE 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:
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:
Manufacturer:
AISAN
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 system:
Helical gear
Primary reduction ratio:
31/14 (2.214)
Secondary reduction system:
Helical gear
-20 -10 0
10 20 30
40
50 ˚C
SAE 10W-30
SAE 15W-40SAE 20W-40SAE 20W-50
SAE 10W-40SAE 10W-50
Page 92 of 98
SPECIFICATIONS
8-3
1
2
3
4
5
6
7
8
9Battery:
Model:
GT9B-4
Voltage, capacity:
12 V, 8.0 Ah
Headlight:
Bulb type:
Halogen bulb
Bulb voltage, wattage
×
quantity:
Headlight:
12 V, 60 W/55.0 W
×
2
Tail/brake light:
LED
Front turn signal light:
12 V, 21.0 W
×
2
Rear turn signal light:
12 V, 21.0 W
×
2
Auxiliary light:
12 V, 5.0 W
×
2
License plate light:
12 V, 5.0 W
×
1
Meter lighting:
12 V, 2.0 W
×
3
High beam indicator light:
12 V, 1.4 W
×
1
Turn signal indicator light:
12 V, 1.4 W
×
2
Engine trouble warning light:
12 V, 1.4 W
×
1
ABS warning light:
YP400A 12 V, 1.4 W
×
1
Immobilizer system indicator light:
LED
Fuses:
Main fuse:
40.0 A
Headlight fuse:
25.0 A
Signaling system fuse:
10.0 A
Ignition fuse:
10.0 A
Radiator fan fuse:
10.0 A
Hazard fuse:
10.0 A
Fuel injection system fuse:
10.0 A
ABS control unit fuse:
YP400A 10.0 A
ABS motor fuse:
YP400A 30.0 A
Backup fuse:
10.0 A