2020 YAMAHA YZF-R125 radiator

Instrument and control functions
3-3
3 For vehicles with a radiator fan, the ra-
diator fan(s) automatically switch on or
off according to the coolant tempera-
ture.
TIP
When the vehicle is turned on, the light
will come on for a few seconds, and
then go off. If the light does not come
on, or if the light remains on, have a
Yamaha dealer check the vehicle.
NOTICE
ECA10022
Do not continue to operate the en-
gine if it is overheating.
EAU11487Engine trouble warning light “ ”
This warning light comes on if a prob-
lem is detected in the engine. If this oc-
curs, have a Yamaha dealer check the
vehicle as soon as possible.
TIP
When the vehicle is turned on, the light
should come for a few seconds and
then go off. Otherwise, have a Yamaha
dealer check the electrical circuit.
EAU69895ABS warning light “ ”
This warning light comes on when the
vehicle is first turned on, and goes off
after starting riding. If the warning light
comes on while riding, the anti-lock
brake system may not work correctly.
WARNING
EWA16043
If the ABS warning light does not
turn off after reaching 10 km/h (6
mi/h), or if the warning light comes
on while riding: Use extra caution to avoid pos-
sible wheel lock during emer-
gency braking.
Have a Yamaha dealer check
the vehicle as soon as possible.
EAU80372Shift light
This light can be set to come on and go
off at select engine speeds. (See page
3-9.)
TIP
When the vehicle is turned on, the light
will come on for a few seconds and
then go off. If the light does not come
on, have a Yamaha dealer check the
vehicle.
ABS
UB5GE1E0.book Page 3 Monday, August 26, 2019 3:02 PM

Periodic maintenance and adjustment
6-13
6
EAU20071
Coolant
The coolant level should be checked
before each ride. In addition, the cool-
ant must be changed at the intervals
specified in the periodic maintenance
and lubrication chart.
EAUE3460To check the coolant level
1. Place the vehicle on a level sur-
face.
2. Remove cowling C of left side.
(See page 6-7.)
3. Hold the vehicle in an upright po-
sition.
TIP
The coolant level must be
checked on a cold engine since
the level varies with engine tem-
perature.
Make sure that the vehicle is posi-
tioned straight up when checking
the coolant level. A slight tilt to the
side can result in a false reading.
4. Check the coolant level in the
coolant reservoir.
TIP
The coolant should be between the
minimum and maximum level marks.
5. If the coolant is at or below the
minimum level mark, remove the
coolant reservoir cap.
6. Add coolant to the maximum level
mark, and then install the coolant
reservoir cap. WARNING! Re-
move only the coolant reservoir
cap. Never attempt to remove
the radiator cap when the en-
gine is hot.
[EWA15162] NOTICE: If
coolant is not available, use dis-
tilled water or soft tap water in-
stead. 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 possi-
ble, otherwise the cooling sys-
tem will not be protected
1. Coolant reservoir
2. Maximum level mark
3. Minimum level mark
1. Coolant reservoir cap
1
2
3FULL
LOW
ZAUE3384
1
ZAUE3385
UB5GE1E0.book Page 13 Monday, August 26, 2019 3:02 PM

Periodic maintenance and adjustment
6-14
6against frost and 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.
[ECA10473]
7. Install the cowling.
EAU33032Changing the coolant
The coolant must be changed at the in-
tervals specified in the periodic mainte-
nance and lubrication chart. Have a
Yamaha dealer change the coolant.
WARNING! Never attempt to remove
the radiator cap when the engine is
hot.
[EWA10382]EAUM2391
Replacing the air filter ele-
ment and cleaning the check
hose
The air filter element should be re-
placed at the intervals specified in the
periodic maintenance and lubrication
chart. Have a Yamaha dealer replace
the air filter element more frequently if
you are riding in unusually wet or dusty
areas. In addition, the air filter check
hose must be frequently checked and
cleaned if necessary.
To clean the air filter check hose
1. Check the hose on the side of the
air filter case for accumulated dirt
or water.
2. If dirt or water is visible, remove
the hose, clean it, and then install
it.
Coolant reservoir capacity (up to
the maximum level mark):
0.15 L (0.16 US qt, 0.13 Imp.qt)
1. Air filter check hose
ZAUM1594
UB5GE1E0.book Page 14 Monday, August 26, 2019 3:02 PM

Periodic maintenance and adjustment
6-38
6
EAU86430Engine overheating
WARNING
EWAT1041
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 ro-
tate the cap counterclockwise to the detent to allow any residual pres-
sure 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.Add coolant.
(See TIP.)
The coolant level is
OK.
There is no leakage.
There is leakage.
The coolant level is
low.
Check the cooling
system for leakage.
Have a Yamaha
dealer check and
repair the cooling
system.
Start the engine. If the engine overheats again,
have a Yamaha dealer check and repair the cooling
system.
UB5GE1E0.book Page 38 Monday, August 26, 2019 3:02 PM

Specifications
8-1
8
Dimensions:
Overall length:
1990 mm (78.3 in)
Overall width:
755 mm (29.7 in)
Overall height:
1140 mm (44.9 in)
Seat height:
820 mm (32.3 in)
Wheelbase:
1325 mm (52.2 in)
Ground clearance:
160 mm (6.30 in)
Minimum turning radius:
2.9 m (9.51 ft)
Weight:
Curb weight:
142 kg (313 lb)
Engine:
Combustion cycle:
4-stroke
Cooling system:
Liquid cooled
Valve train:
SOHC
Number of cylinders:
Single cylinder
Displacement:
124 cm³
Bore × stroke:
52.0 × 58.6 mm (2.05 × 2.31 in)
Starting system:
Electric starter
Engine oil:
Recommended brand:
SAE viscosity grades:
10W-40
Recommended engine oil grade:
API service SG type or higher, JASO
standard MA
Engine oil quantity:
Oil change:
0.85 L (0.90 US qt, 0.75 Imp.qt)
With oil filter removal:
0.95 L (1.00 US qt, 0.84 Imp.qt)
Coolant quantity:
Coolant reservoir (up to the maximum level
mark):
0.15 L (0.16 US qt, 0.13 Imp.qt)
Radiator (including all routes):
0.49 L (0.52 US qt, 0.43 Imp.qt)
Fuel:
Recommended fuel:
Unleaded gasoline (E10 acceptable)
Octane number (RON):
95
Fuel tank capacity:
11 L (2.9 US gal, 2.4 Imp.gal)
Fuel reserve amount:
3.0 L (0.79 US gal, 0.66 Imp.gal)
Fuel injection:
Throttle body:
ID mark:
B5G1 00
Drivetrain:
Gear ratio:
1st:
2.833 (34/12)
2nd:
1.875 (30/16)
3rd:
1.364 (30/22)
4th:
1.143 (24/21)
5th:
0.957 (22/23)
6th:
0.840 (21/25)
Front tire:
Type:
Tubeless
Size:
100/80-17M/C 52S
Manufacturer/model:
MICHELIN PILOT STREET
Rear tire:
Type:
Tubeless
Size:
140/70-17M/C 66S
Manufacturer/model:
MICHELIN PILOT STREET
Loading:
Maximum load:
178 kg (392 lb)
UB5GE1E0.book Page 1 Monday, August 26, 2019 3:02 PM