2010 YAMAHA YBR125 engine

PERIODIC MAINTENANCE AND ADJUSTMENT
6-36
6
EAU45731
Troubleshooting chart
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.
There is no fuel.
Check the compression.
Supply fuel.
The engine does not start.
Check the compression.
Operate the electric starter
or the kickstarter.2. Compression
There is compression.
There is no compression.
Check the ignition.
Have a Yamaha dealer
check the vehicle.
Remove the spark plug
and check the electrodes.3. Ignition
Wipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug.
Have a Yamaha dealer check the vehicle.
The engine does not start.
Have a Yamaha dealer
check the vehicle.
The engine does not start.
Check the battery.
Operate the electric starter.4. Battery
The engine turns over
quickly.
The engine turns over
slowly.
The battery is good.Check the battery lead connections,
and charge the battery if necessary.
DryWet
Operate the electric starter
or the kickstarter.
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MOTORCYCLE CARE AND STORAGE
7-1
7
EAU37833
Matte color caution NOTICE
ECA15192
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.
EAU26004
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 motor-
cycle. Frequent and proper care does
not only comply with the terms of the
warranty, but it will also keep your mo-
torcycle 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 covers
as well as all electrical couplers
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 de-
greaser off with water.
Cleaning
NOTICE
ECA10772


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-
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
U51DE0E0.book Page 1 Monday, November 2, 2009 10:34 AM

MOTORCYCLE CARE AND STORAGE
7-2
7off 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 products, solvent or
thinner, fuel (gasoline), rust re-
movers or inhibitors, brake flu-
id, 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 or
scratching. Some cleaning com-
pounds for plastic may leave
scratches on the windshield.Test the product on a small hid-
den part of the windshield to
make sure that it does not leave
any marks. If the windshield is
scratched, use a quality plastic
polishing compound after
washing.
After normal useRemove 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.
After riding in the rain, near the sea oron salt-sprayed roadsSince 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.
TIPSalt sprayed on roads in the winter may
remain well into spring.1. Clean the motorcycle with cold wa-
ter and a mild detergent, after the
engine has cooled down.
NOTICE: Do not use warm water
since it increases the corrosive
action of the salt.
[ECA10791]
2. Apply a corrosion protection spray
on all metal, including chrome- and
nickel-plated, surfaces to prevent
corrosion.
After cleaning
1. Dry the motorcycle with a chamois
or an absorbing cloth.
2. Immediately dry the drive chain
and lubricate it to prevent it from
rusting.
3. Use a chrome polish to shine
chrome, aluminum and stainless-
steel parts, including the exhaust
system. (Even the thermally in-
duced discoloring of stainless-
steel exhaust systems can be re-
moved through polishing.)
U51DE0E0.book Page 2 Monday, November 2, 2009 10:34 AM

MOTORCYCLE CARE AND STORAGE
7-4
73. Perform the following steps to pro-
tect 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 cylinder
head 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.)
e. Remove the spark plug cap
from the spark plug, and then
install the spark plug and the
spark plug cap. WARNING! To
prevent damage or injury
from sparking, make sure to
ground the spark plug elec-
trodes while turning the en-
gine over.
[EWA10951]
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
6-26.
TIPMake any necessary repairs before
storing the motorcycle.
U51DE0E0.book Page 4 Monday, November 2, 2009 10:34 AM

SPECIFICATIONS
8-1
8
Dimensions:Overall length:
1985 mm (78.1 in)
Overall width:
745 mm (29.3 in)
Overall height:
1080 mm (42.5 in)
Seat height:
780 mm (30.7 in)
Wheelbase:
1290 mm (50.8 in)
Ground clearance:
160 mm (6.30 in)
Minimum turning radius:
2270 mm (89.4 in)Weight:With oil and fuel:
125 kg (276 lb)Engine:Engine type:
Air cooled 4-stroke, SOHC
Cylinder arrangement:
Forward-inclined single cylinder
Displacement:
123 cm³
Bore × stroke:
54.0 × 54.0 mm (2.13 × 2.13 in)
Compression ratio:
10.00 :1
Starting system:
Electric starter and kickstarter
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
standard MA
Engine oil quantity:
Periodic oil change:
1.00 L (1.06 US qt, 0.88 Imp.qt)Air filter:Air filter element:
Dry elementFuel:Recommended fuel:
Regular unleaded gasoline only
Fuel tank capacity:
13.0 L (3.43 US gal, 2.86 Imp.gal)
Fuel reserve amount:
3.4 L (0.90 US gal, 0.75 Imp.gal)
Fuel injection:Throttle body:
ID mark:
51D1 00Spark plug(s):Manufacturer/model:
NGK/CR6HSA
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)Clutch:Clutch type:
Wet, multiple-discTransmission:Primary reduction system:
Helical gear
Primary reduction ratio:
68/20 (3.400)
Secondary reduction system:
Chain drive
Secondary reduction ratio:
45/14 (3.214)
Transmission type:
Constant mesh 5-speed
Operation:
Left foot operation
Gear ratio:
1st:
37/14 (2.643)
2nd:
32/18 (1.778)
3rd:
25/19 (1.316)
4th:
23/22 (1.045)
–20 –10 0
1020 30 40 50 C 10 30 50 70 90 110 0 130 F
SAE 10W-30
SAE 15W-40SAE 20W-40SAE 20W-50
SAE 10W-40SAE 10W-50
U51DE0E0.book Page 1 Monday, November 2, 2009 10:34 AM

SPECIFICATIONS
8-3
8
Auxiliary light:
12 V, 5.0 W × 1
Meter lighting:
12 V, 1.7 W × 3
Neutral indicator light:
12 V, 2.0 W × 1
High beam indicator light:
12 V, 2.0 W × 1
Turn signal indicator light:
12 V, 2.0 W × 2
Engine trouble warning light:
12 V, 2.0 W × 1Fuse:Fuse:
15.0 A
U51DE0E0.book Page 3 Monday, November 2, 2009 10:34 AM

INDEX
AAir filter element, cleaning .................... 6-10
Auxiliary light bulb, replacing ................ 6-31BBattery .................................................. 6-26
Brake and clutch levers, checking and
lubricating ........................................... 6-23
Brake fluid, changing ............................ 6-20
Brake fluid level, checking .................... 6-19
Brake lever ............................................. 3-5
Brake light switches .............................. 6-17
Brake pads and shoes, checking.......... 6-18
Brake pedal ............................................ 3-6
Brake pedal, checking and
lubricating ........................................... 6-24
Brake pedal free play, adjusting ........... 6-16CCables, checking and lubricating .......... 6-22
Care ........................................................ 7-1
Carrier................................................... 3-10
Catalytic converters ................................ 3-8
Centerstand and sidestand, checking
and lubricating .................................... 6-24
Clutch lever............................................. 3-5
Clutch lever free play, adjusting ........... 6-15DDimmer switch ........................................ 3-4
Drive chain, cleaning and lubricating .... 6-22
Drive chain slack .................................. 6-20EEngine break-in ...................................... 5-3
Engine idling speed, checking .............. 6-12
Engine oil ................................................ 6-9
Engine trouble warning light ................... 3-2
FFront brake lever free play, checking .... 6-16
Front fork, checking...............................6-25
Fuel ......................................................... 3-7
Fuel consumption, tips for reducing ........ 5-3
Fuel gauge .............................................. 3-4
Fuel tank cap........................................... 3-6
Fuse, replacing...................................... 6-28HHandlebar switches ................................. 3-4
Headlight bulb, replacing....................... 6-29
High beam indicator light......................... 3-2
Horn switch ............................................. 3-4IIdentification numbers ............................. 9-1
Ignition circuit cut-off system ................. 3-11
Indicator and warning lights .................... 3-2KKickstarter ............................................... 3-9MMain switch/steering lock ........................ 3-1
Maintenance and lubrication, periodic..... 6-3
Maintenance, emission control system ... 6-2
Matte color, caution .................................7-1
Model label .............................................. 9-1NNeutral indicator light .............................. 3-2PPanels, removing and installing .............. 6-6
Parking ....................................................5-4
Part locations .......................................... 2-1SSafety information ...................................1-1
Self-diagnosis device .............................. 3-3Shifting .................................................... 5-2
Shift pedal ............................................... 3-5
Shift pedal, checking............................. 6-17
Shock absorber assemblies, adjusting ... 3-9
Sidestand .............................................. 3-10
Spark plug, checking .............................. 6-7
Specifications.......................................... 8-1
Speedometer unit ................................... 3-3
Starting the engine.................................. 5-1
Start switch ............................................. 3-4
Steering, checking ................................ 6-26
Storage ................................................... 7-3
Swingarm pivots, lubricating ................. 6-25
TTachometer............................................. 3-3
Tail/brake light bulb, replacing .............. 6-30
Throttle cable free play, checking ......... 6-12
Throttle grip and cable, checking and
lubricating ........................................... 6-23
Tires ...................................................... 6-13
Tool kit .................................................... 6-1
Troubleshooting .................................... 6-35
Troubleshooting chart ........................... 6-36
Turn signal indicator lights ...................... 3-2
Turn signal light bulb, replacing ............ 6-31
Turn signal switch ................................... 3-4VValve clearance .................................... 6-13
Vehicle identification number .................. 9-1WWheel bearings, checking..................... 6-26
Wheel (front) ......................................... 6-32
Wheel (rear) .......................................... 6-33
Wheels .................................................. 6-15
U51DE0E0.book Page 1 Monday, November 2, 2009 10:34 AM