engine YAMAHA YBR125 2008 Owner's Guide

PERIODIC MAINTENANCE AND MINOR REPAIR
6-37
6
EAU45730
Troubleshooting chart
WARNING
EWA10840
Keep away open flames and do not smoke while checking or working on the fuel system.
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.
U27SE0E0.book Page 37 Friday, February 22, 2008 8:54 AM

MOTORCYCLE CARE AND STORAGE
7-1
7
EAU37833
Matte color caution CAUTION:
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.
EAU26002
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
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 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
CAUTION:
ECA10771


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. Use
only a soft, clean cloth or
sponge with mild detergent and
water to clean plastic.


Do not use any harsh chemical
products on plastic parts. Be
sure to avoid using cloths or
sponges which have been in
U27SE0E0.book Page 1 Friday, February 22, 2008 8:54 AM

MOTORCYCLE CARE AND STORAGE
7-2
7 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 isscratched, use a quality plastic
polishing compound after
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.
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.NOTE:Salt sprayed on roads in the winter mayremain well into spring.1. Clean the motorcycle with cold wa-
ter and a mild detergent, after the
engine has cooled down.
CAUTION:
ECA10790
Do not use warm water since it in-
creases the corrosive action of thesalt.
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.)
U27SE0E0.book Page 2 Friday, February 22, 2008 8:54 AM

MOTORCYCLE CARE AND STORAGE
7-4
7 3. 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
EWA10950
To prevent damage or injury from
sparking, make sure to ground the
spark plug electrodes while turningthe engine over.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
6-27.
NOTE:Make any necessary repairs beforestoring the motorcycle.
U27SE0E0.book Page 4 Friday, February 22, 2008 8:54 AM

SPECIFICATIONS
8-1
8
Dimensions:Overall length:
2055 mm (80.9 in)
Overall width:
845 mm (33.3 in)
Overall height:
1125 mm (44.3 in)
Seat height:
760 mm (29.9 in)
Wheelbase:
1290 mm (50.8 in)
Ground clearance:
140 mm (5.51 in)
Minimum turning radius:
1750 mm (68.9 in)Weight:With oil and fuel:
130.0 kg (287 lb)Engine:Engine type:
Air cooled 4-stroke, SOHC
Cylinder arrangement:
Forward-inclined single cylinder
Displacement:
123.7 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: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
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:
12.0 L (3.17 US gal, 2.64 Imp.gal)
Fuel reserve amount:
3.0 L (0.79 US gal, 0.66 Imp.gal)
Fuel injection:Throttle body:
Manufacturer:
MIKUNI
Type/quantity:
AC26-6/1Spark 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:
43/14 (3.071)
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)
-20 -10 0
10 20 30
40
50 ˚C
SAE 10W-30
SAE 15W-40SAE 20W-40SAE 20W-50
SAE 10W-40SAE 10W-50
U27SE0E0.book Page 1 Friday, February 22, 2008 8:54 AM

SPECIFICATIONS
8-3
8
Rear turn signal light:
12 V, 10.0 W × 2
Auxiliary light:
12 V, 5.0 W × 1
Meter lighting:
12 V, 1.7 W × 4
Neutral indicator light:
14 V, 3.0 W × 1
High beam indicator light:
14 V, 3.0 W × 1
Turn signal indicator light:
14 V, 3.0 W × 1
Engine trouble warning light:
14 V, 3.0 W × 1Fuse:Fuse:
15.0 A
U27SE0E0.book Page 3 Friday, February 22, 2008 8:54 AM

INDEX
AAir filter element, cleaning .................... 6-10
Auxiliary light bulb, replacing ................ 6-31BBattery .................................................. 6-27
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 pads and shoes, checking.......... 6-19
Brake pedal ............................................ 3-6
Brake pedal, checking and
lubricating ........................................... 6-24
Brake pedal free play, adjusting ........... 6-17CCables, checking and lubricating .......... 6-23
Care ........................................................ 7-1
Carrier..................................................... 3-9
Catalytic converters ................................ 3-8
Centerstand and sidestand,
checking and lubricating ..................... 6-24
Clutch lever............................................. 3-5
Clutch lever free play, adjusting ........... 6-16DDimmer switch ........................................ 3-4
Drive chain, cleaning and lubricating .... 6-22
Drive chain slack .................................. 6-21EEngine 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 .... 6-17
Front fork, checking...............................6-25
Fuel ......................................................... 3-7
Fuel consumption, tips for reducing ........ 5-3
Fuel gauge .............................................. 3-3
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 ................. 3-10
Indicator and warning lights .................... 3-2KKey identification number ........................ 9-1
Kickstarter ............................................... 3-8MMain switch/steering lock ........................ 3-1
Matte color, caution .................................7-1
Model label .............................................. 9-2NNeutral indicator light .............................. 3-2PPanels, removing and installing .............. 6-6
Parking ....................................................5-4
Part locations .......................................... 2-1
Periodic maintenance and
lubrication chart.....................................6-2
Pre-operation check list........................... 4-2
RRear brake light switch, adjusting ......... 6-18SSafety information ................................... 1-1
Self-diagnosis device .............................. 3-3
Shifting .................................................... 5-2
Shift pedal ............................................... 3-5
Shift pedal, checking............................. 6-18
Shock absorber assemblies, adjusting ... 3-8
Sidestand ................................................ 3-9
Spark plug, checking .............................. 6-7
Specifications.......................................... 8-1
Speedometer unit ................................... 3-2
Starting the engine.................................. 5-1
Start switch ............................................. 3-4
Steering, checking ................................ 6-26
Storage ................................................... 7-3
Swingarm pivots, lubricating ................. 6-25TTachometer............................................. 3-3
Tail/brake light bulb, replacing .............. 6-30
Throttle cable free play, adjusting ......... 6-12
Throttle grip and cable,
checking and lubricating ..................... 6-23
Tires ...................................................... 6-13
Tool kit .................................................... 6-1
Troubleshooting .................................... 6-36
Troubleshooting chart ........................... 6-37
Turn signal indicator light ........................ 3-2
Turn signal light bulb, replacing ............ 6-31
Turn signal switch ................................... 3-4VValve clearance .................................... 6-13
Vehicle identification number .................. 9-1
U27SE0E0.book Page 1 Friday, February 22, 2008 8:54 AM