engine YAMAHA YZF-R125 2016 Service Manual

Periodic maintenance and adjustment
6-26
6
EAU22762
Drive chain slack
The drive chain slack should be
checked before each ride and adjusted
if necessary.
EAUM3551To check the drive chain slack
1. Place the motorcycle on the side-
stand.
TIP
When checking and adjusting the drive
chain slack, there should be no weight
on the motorcycle.
2. Shift the transmission into the
neutral position.
3. Measure the drive chain slack at
the arrow mark on the swingarm
as shown in the illustration.
4. If the drive chain slack is incorrect,
adjust it as follows.
EAU34318To adjust the drive chain slack
Consult a Yamaha dealer before ad-
justing the drive chain slack.
1. Loosen the axle nut and the lock-
nut on each side of the swingarm.2. To tighten the drive chain, turn the
drive chain slack adjusting bolt on
each side of the swingarm in di-
rection (a). To loosen the drive
chain, turn the adjusting bolt on
each side of the swingarm in di-
rection (b), and then push the rear
wheel forward. NOTICE: Improp-
er drive chain slack will over-
load the engine as well as other
vital parts of the motorcycle and
can lead to chain slippage or
breakage. To prevent this from
occurring, keep the drive chain
slack within the specified limits.
[ECA10572]
TIP
Using the alignment marks on each
side of the swingarm, make sure that
both drive chain pullers are in the same
position for proper wheel alignment.
3. Tighten the axle nut, then the lock-
nuts to their specified torques.
Drive chain slack:
35.0–45.0 mm (1.38–1.77 in)
1. Drive chain slack
ZAUM1182
1. Axle nut
2. Drive chain slack adjusting bolt
3. Locknut
4. Alignment marks
ZAUM1183
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Periodic maintenance and adjustment
6-27
6 4. Make sure that the drive chain
pullers are in the same position,
the drive chain slack is correct,
and the drive chain moves
smoothly.
EAU23026
Cleaning and lubricating the
drive chain
The drive chain must be cleaned and
lubricated at the intervals specified in
the periodic maintenance and lubrica-
tion chart, otherwise it will quickly wear
out, especially when riding in dusty or
wet areas. Service the drive chain as
follows.
NOTICE
ECA10584
The drive chain must be lubricated
after washing the motorcycle, riding
in the rain or riding in wet areas.
1. Clean the drive chain with kero-
sene and a small soft brush.
NOTICE: To prevent damaging
the O-rings, do not clean the
drive chain with steam cleaners,
high-pressure washers or inap-
propriate solvents.
[ECA11122]
2. Wipe the drive chain dry.
3. Thoroughly lubricate the drive
chain with a special O-ring chain
lubricant. NOTICE: Do not use
engine oil or any other lubri-
cants for the drive chain, as they
may contain substances that
could damage the O-rings.
[ECA11112]
Tightening torques:
Axle nut:
85 Nm (8.5 m·kgf, 61 ft·lbf)
Locknut:
16 Nm (1.6 m·kgf, 12 ft·lbf)
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Periodic maintenance and adjustment
6-38
6
EAU24351
Supporting the motorcycle
Since this model is not equipped with a
centerstand, follow these precautions
when removing the front and rear
wheel or performing other mainte-
nance requiring the motorcycle to
stand upright. Check that the motorcy-
cle is in a stable and level position be-
fore starting any maintenance. A
strong wooden box can be placed un-
der the engine for added stability.
To service the front wheel
1. Stabilize the rear of the motorcy-
cle by using a motorcycle stand
or, if an additional motorcycle
stand is not available, by placing a
jack under the frame in front of the
rear wheel.
2. Raise the front wheel off the
ground by using a motorcycle
stand.
To service the rear wheel
Raise the rear wheel off the ground by
using a motorcycle stand or, if a motor-
cycle stand is not available, by placing
a jack either under each side of the
frame in front of the rear wheel or under
each side of the swingarm.
EAU44792
Front wheel (for non-ABS
models)
WARNING
EWA14841
For the ABS model, have a Yamaha
dealer remove and install the wheel.
EAU56531
To remove the front wheel
WARNING
EWA10822
To avoid injury, securely support the
vehicle so there is no danger of it
falling over.
1. Loosen the front wheel axle pinch
bolts, then the wheel axle and the
brake caliper bolts.
1. Axle bolt
2. Front wheel axle pinch bolt A
3. Front wheel axle pinch bolt B
ZAUM12153
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Periodic maintenance and adjustment
6-42
6
EAU68070
Troubleshooting charts
Starting problems or poor engine performance
1. FuelThere is enough fuel.
There is no fuel.Supply fuel.
The engine turns over
quickly.
Operate the electric
starter.
Check the
compression.
The engine turns over
slowly.
Wipe off with a dry
cloth and correct the
spark plug gap, or
replace the spark
plug.
Check the electrolyte
and battery lead
connections, and
charge the battery if
necessary.
The engine does not
start.
Have a Yamaha
dealer check the
vehicle.
4. BatteryThe battery is good.
3. IgnitionWet
Dry
The engine does not
start.
Check the
compression.
Have a Yamaha
dealer check the
vehicle.The engine does not
start.
Check the battery.
Remove the spark
plug and check
the electrodes.
Check the fuel level
in the fuel tank.
Operate the electric
starter.
Operate the electric
starter.
There is compression.
There is no
compression.Have a Yamaha dealer check the vehicle.
Check the ignition.2. Compression
U5D7E6E0.book Page 42 Wednesday, June 17, 2015 10:25 AM

Periodic maintenance and adjustment
6-43
6 Engine overheating
WARNING
EWA10401
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 counter-
clockwise 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.
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.
U5D7E6E0.book Page 43 Wednesday, June 17, 2015 10:25 AM

Motorcycle care and storage
7-1
7
EAU37834
Matte color caution
NOTICE
ECA15193
Some models are equipped with
matte colored finished parts. Be
sure to consult a Yamaha dealer for
advice on what products to use be-
fore cleaning the vehicle. Using a
brush, harsh chemical products or
cleaning compounds when cleaning
these parts will scratch or damage
their surface. Wax also should not
be applied to any matte colored fin-
ished parts.
EAUM2453
Care
While the open design of a motorcycle
reveals the attractiveness of the tech-
nology, it also makes it more vulnera-
ble. Rust and corrosion can develop
even if high-quality components are
used. A rusty exhaust pipe may go un-
noticed on a car, however, it detracts
from the overall appearance of a mo-
torcycle. Frequent and proper care
does not only comply with the terms of
the warranty, but it will also keep your
motorcycle looking good, extend its
life and optimize its performance.
Before cleaning
1. Cover the muffler outlet with a
plastic bag after the engine has
cooled down.
2. Make sure that all caps and cov-
ers as well as all electrical cou-
plers and connectors, including
the spark plug cap, are tightly in-
stalled.
3. Remove extremely stubborn dirt,
like oil burnt onto the crankcase,
with a degreasing agent and a
brush, but never apply such prod-
ucts onto seals, gaskets, sprock-
ets, the drive chain and wheel
axles. Always rinse the dirt and
degreaser off with water.
Cleaning
NOTICE
ECA10773
Avoid using strong acidic wheel
cleaners, especially on spoked
wheels. If such products are
used on hard-to-remove dirt, do
not leave the cleaner on the af-
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Motorcycle care and storage
7-2
7 fected area any longer than in-
structed. Also, thoroughly rinse
the area off with water, immedi-
ately dry it, and then apply a cor-
rosion protection spray.
Improper cleaning can damage
plastic parts (such as cowlings,
panels, windshields, headlight
lenses, meter lenses, etc.) and
the mufflers. Use only a soft,
clean cloth or sponge with wa-
ter to clean plastic. However, if
the plastic parts cannot be thor-
oughly cleaned with water, di-
luted mild detergent with water
may be used. Be sure to rinse
off any detergent residue using
plenty of water, as it is harmful
to plastic parts.
Do not use any harsh chemical
products on plastic parts. Be
sure to avoid using cloths or
sponges which have been in
contact with strong or abrasive
cleaning pro
ducts, solvent or
thinner, fuel (gasoline), rust re-
movers or inhibitors, brake fluid,
antifreeze or electrolyte.
Do not use high-pressure wash-
ers or steam-jet cleaners since
they cause water seepage and
deterioration in the following ar-
eas: seals (of wheel and swing-
arm bearings, fork and brakes),
electric components (couplers,
connectors, instruments,
switches and lights), breather
hoses and vents.
For motorcycles equipped with
a windshield: Do not use strong
cleaners or hard sponges as
they will cause dulling orscratching. Some cleaning
compounds for plastic may
leave scratches on the wind-
shield. Test the product on a
small hidden part of the wind-
shield to make sure that it does
not leave any marks. If the wind-
shield is scratched
, use a quality
plastic polishing compound af-
ter washing.
After normal use
Remove dirt with warm water, a mild
detergent, and a soft, clean sponge,
and then rinse thoroughly with clean
water. Use a toothbrush or bottlebrush
for hard-to-reach areas. Stubborn dirt
and insects will come off more easily if
the area is covered with a wet cloth for
a few minutes before cleaning. Use the
special sponge, which is located under
the tool kit, to clean the muffler and to
remove any discoloration from it.
After riding in the rain, near the sea or
on salt-sprayed roads
Since sea salt or salt sprayed on roads
during winter are extremely corrosive
in combination with water, carry out
the following steps after each ride in
the rain, near the sea or on salt-
sprayed roads.
TIP
Salt sprayed on roads in the winter
may remain well into spring.
1. Clean the motorcycle with cold
water and a mild detergent, after
the engine has cooled down.
NOTICE: Do not use warm wa-
ter since it increases the corro-
sive action of the salt.
[ECA10792]
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Motorcycle care and storage
7-4
7
EAU43204
Storage
Short-term
Always store your motorcycle in a cool,
dry place and, if necessary, protect it
against dust with a porous cover. Be
sure the engine and the exhaust sys-
tem are cool before covering the mo-
torcycle.
NOTICE
ECA10811
Storing the motorcycle in a
poorly ventilated room or cover-
ing it with a tarp, while it is still
wet, will allow water and humid-
ity to seep in and cause rust.
To prevent corrosion, avoid
damp cellars, stables (because
of the presence of ammonia)
and areas where strong chemi-
cals are stored.
Long-term
Before storing your motorcycle for sev-
eral months:
1. Follow all the instructions in the
“Care” section of this chapter.
2. Fill up the fuel tank and add fuel
stabilizer (if available) to prevent
the fuel tank from rusting and the
fuel from deteriorating.
3. Perform the following steps to
protect the cylinder, piston rings,
etc. from corrosion.
a. Remove the spark plug cap
and spark plug.
b. Pour a teaspoonful of engine
oil into the spark plug bore.
c. Install the spark plug cap onto
the spark plug, and then place
the spark plug on the cylinderhead so that the electrodes are
grounded. (This will limit spark-
ing during the next step.)
d. Turn the engine over several
times with the starter. (This will
coat the cylinder wall with oil.)
WARNING! To prevent dam-
age or injury from sparking,
make sure to ground the
spark plug electrodes while
turning the engine over.
[EWA10952]
e. Remove the spark plug cap
from the spark plug, and then
install the spark plug and the
spark plug cap.
4. Lubricate all control cables and
the pivoting points of all levers and
pedals as well as of the side-
stand/centerstand.
5. Check and, if necessary, correct
the tire air pressure, and then lift
the motorcycle so that both of its
wheels are off the ground. Alterna-
tively, turn the wheels a little every
month in order to prevent the tires
from becoming degraded in one
spot.
6. Cover the muffler outlet with a
plastic bag to prevent moisture
from entering it.
7. Remove the battery and fully
charge it. Store it in a cool, dry
place and charge it once a month.
Do not store the battery in an ex-
cessively cold or warm place [less
than 0 °C (30 °F) or more than 30
°C (90 °F)]. For more information
on storing the battery, see page
6-32.
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Specifications
8-1
8
Dimensions:
Overall length:
1950 mm (76.8 in)
Overall width:
695 mm (27.4 in)
Overall height:
1065 mm (41.9 in)
Seat height:
825 mm (32.5 in)
Wheelbase:
1350 mm (53.1 in)
Ground clearance:
155 mm (6.10 in)
Minimum turning radius:
3100 mm (122.0 in)
Weight:
Curb weight:
140 kg (309 lb) (YZF-R125)
142 kg (313 lb) (YZF-R125A)
Engine:
Engine type:
Liquid cooled 4-stroke, SOHC
Cylinder arrangement:
Single cylinder
Displacement:
124 cm³
Bore × stroke:
52.0 × 58.6 mm (2.05 × 2.31 in)
Compression ratio:
11.2 : 1
Starting system:
Electric starter
Lubrication system:
Wet sump
Engine oil:
Recommended brand:
YAMALUBE
Type:
SAE 10W-30, 10W-40, 15W-40, 20W-40 or
20W-50Recommended engine oil grade:
API service SG type or higher, JASO
standard MA
Engine oil quantity:
Without oil filter element replacement:
0.95 L (1.00 US qt, 0.84 Imp.qt)
With oil filter element replacement:
1.00 L (1.06 US qt, 0.88 Imp.qt)
Coolant quantity:
Coolant reservoir (up to the maximum level
mark):
0.25 L (0.26 US qt, 0.22 Imp.qt)
Radiator (including all routes):
1.00 L (1.06 US qt, 0.88 Imp.qt)
Air filter:
Air filter element:
Dry element
Fuel:
Recommended fuel:
Premium unleaded gasoline (Gasohol (E10)
acceptable)
Fuel tank capacity:
11.5 L (3.04 US gal, 2.53 Imp.gal)
Fuel reserve amount:
3.0 L (0.79 US gal, 0.66 Imp.gal)
Fuel injection:
Throttle body:
ID mark:
5D78 10
Spark plug(s):
Manufacturer/model:
NGK/CR9E
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
Clutch:
Clutch type:
Wet, multiple-disc
–20 –10 0
1020 30 40 50 C 10 30 50 70 90 110 0 130 F
SAE 10W-30
SAE 15W-40
SAE 20W-40
SAE 20W-50
SAE 10W-40
SAE 10W-50
U5D7E6E0.book Page 1 Wednesday, June 17, 2015 10:25 AM

Specifications
8-3
8
Wheel travel:
130 mm (5.1 in)
Rear suspension:
Type:
Swingarm (link suspension)
Spring/shock absorber type:
Coil spring/oil damper
Wheel travel:
114 mm (4.5 in)
Electrical system:
System voltage:
12 V
Ignition system:
TCI
Charging system:
AC magneto
Battery:
Model:
12N5.5-4A / YUASA
Voltage, capacity:
12 V, 5.5 Ah
Headlight:
Bulb type:
Halogen bulb
Bulb voltage, wattage × quantity:
Headlight:
12 V, 55.0 W × 2
Brake/tail light:
LED
Front turn signal light:
12 V, 10.0 W × 2
Rear turn signal light:
12 V, 10.0 W × 2
Auxiliary light:
12 V, 5.0 W × 2
License plate light:
12 V, 5.0 W × 1
Meter lighting:
LED
Neutral indicator light:
LED
High beam indicator light:
LED
Turn signal indicator light:
LED
Fuel level warning light:
LED
Engine trouble warning light:
LEDABS warning light:
LED (YZF-R125A)
Fuse:
Main fuse:
20.0 A
Headlight fuse:
15.0 A
Signaling system fuse:
7.5 A
Ignition fuse:
7.5 A
Radiator fan motor fuse:
5.0 A
ABS control unit fuse:
10.0 A (YZF-R125A)
ABS motor fuse:
30.0 A (YZF-R125A)
ABS solenoid fuse:
20.0 A (YZF-R125A)
Backup fuse:
10.0 A
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