2008 YAMAHA YBR125 engine

OPERATION AND IMPORTANT RIDING POINTS
5-2
53. Start the engine by pushing the
start switch or by pushing the kick-
starter lever down.
NOTE:If the engine fails to start when using
the start switch, release it, wait a few
seconds, and then try again. Each
starting attempt should be as short as
possible to preserve the battery. Do not
crank the engine more than 10 seconds
on any one attempt. If the engine does
not start with the starter motor, try usingthe kickstarter.CAUTION:
ECA11370
The engine trouble warning light
should come on when the key is
turned to “ON”, and then go off after
a few seconds. If the engine trouble
warning light comes on or flashes
after starting, immediately stop the
engine, and have a Yamaha dealercheck the self-diagnosis system.
CAUTION:
ECA11040
For maximum engine life, never ac-
celerate hard when the engine iscold!
EAU16671
Shifting Shifting gears lets you control the
amount of engine power available for
starting off, accelerating, climbing hills,
etc.
The gear positions are shown in the il-
lustration.NOTE:To shift the transmission into the neu-
tral position, press the shift pedal down
repeatedly until it reaches the end of itstravel, and then slightly raise it.1. Shift pedal
2. Neutral position
U27SE0E0.book Page 2 Friday, February 22, 2008 8:54 AM

OPERATION AND IMPORTANT RIDING POINTS
5-3
5
CAUTION:
ECA10260


Even with the transmission in
the neutral position, do not
coast for long periods of time
with the engine off, and do not
tow the motorcycle for long dis-
tances. The transmission is
properly lubricated only when
the engine is running. Inade-
quate lubrication may damage
the transmission.


Always use the clutch while
changing gears to avoid damag-
ing the engine, transmission,
and drive train, which are not
designed to withstand theshock of forced shifting.
EAU16810
Tips for reducing fuel con-
sumption Fuel consumption depends largely on
your riding style. Consider the following
tips to reduce fuel consumption:

Shift up swiftly, and avoid high en-
gine speeds during acceleration.


Do not rev the engine while shifting
down, and avoid high engine
speeds with no load on the engine.


Turn the engine off instead of let-
ting it idle for an extended length of
time (e.g., in traffic jams, at traffic
lights or at railroad crossings).
EAU16830
Engine break-in There is never a more important period
in the life of your engine than the period
between 0 and 1000 km (600 mi). For
this reason, you should read the follow-
ing material carefully.
Since the engine is brand new, do not
put an excessive load on it for the first
1000 km (600 mi). The various parts in
the engine wear and polish themselves
to the correct operating clearances.
During this period, prolonged full-throt-
tle operation or any condition that might
result in engine overheating must be
avoided.
EAU37250
0–500 km (0–300 mi)
Avoid prolonged operation above 6000
r/min.
After every hour of operation, stop the
engine, and then let it cool for five to ten
minutes.
Vary the engine speed from time to
time. Do not operate the engine at one
set throttle position.
U27SE0E0.book Page 3 Friday, February 22, 2008 8:54 AM

OPERATION AND IMPORTANT RIDING POINTS
5-4
5500–1000 km (300–600 mi)
Avoid prolonged operation above 7500
r/min.
Rev the engine freely through the
gears, but do not use full throttle at any
time.
CAUTION:
ECA10280
After 1000 km (600 mi) of operation,the engine oil must be changed.
1000 km (600 mi) and beyond
The vehicle can now be operated nor-
mally.CAUTION:
ECA10310


Keep the engine speed out of
the tachometer red zone.


If any engine trouble should oc-
cur during the engine break-in
period, immediately have a
Yamaha dealer check the vehi-cle.
EAU17212
Parking When parking, stop the engine, and
then remove the key from the main
switch.
WARNING
EWA10310


Since the engine and exhaust
system can become very hot,
park in a place where pedestri-
ans or children are not likely to
touch them.


Do not park on a slope or on soft
ground, otherwise the vehiclemay overturn.
CAUTION:
ECA10380
Never park in an area where there
are fire hazards such as grass orother flammable materials.
U27SE0E0.book Page 4 Friday, February 22, 2008 8:54 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-4
6
15*Chassis fastenersMake sure that all nuts, bolts and
screws are properly tightened.√√√√√
16Brake lever pivot
shaftLubricate with silicone grease.√√√√√
17Brake pedal pivot
shaftLubricate with lithium-soap-based
grease.√√√√√
18Clutch lever pivot
shaftLubricate with lithium-soap-based
grease.√√√√√
19Sidestand, center-
standCheck operation.
Lubricate.√√√√√
20*Sidestand switchCheck operation.√√√√√√
21*Front forkCheck operation and for oil leak-
age.√√√√
22*Shock absorber as-
sembliesCheck operation and shock ab-
sorbers for oil leakage.√√√√
23*Fuel injectionCheck engine idle speed.√√√√√√
24 Engine oilChange.
Check oil level and vehicle for oil
leakage.√√√√√√
25*Front and rear brake
switchesCheck operation.√√√√√√
26Moving parts and
cablesLubricate.√√√√√ NO. ITEM CHECK OR MAINTENANCE JOBODOMETER READING
ANNUAL
CHECK 1000 km
(600 mi)6000 km
(3500 mi)12000 km
(7000 mi)18000 km
(10500 mi)24000 km
(14000 mi)U27SE0E0.book Page 4 Friday, February 22, 2008 8:54 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-7
6 2. While pushing the panel inward,
turn the key counterclockwise to
the original position, remove it, and
then close the panel lock cover.
EAU37070
Panel B
To remove the panel1. Remove the screw.
2. Pull the front of the panel out, and
then slide the panel forward to re-
lease it in the rear.To install the panel
1. Secure the rear of the panel, and
then push the front of the panel in.
2. Install the screw.
EAU19603
Checking the spark plug The spark plug is an important engine
component, which is easy to check.
Since heat and deposits will cause any
spark plug to slowly erode, the spark
plug should be removed and checked
in accordance with the periodic mainte-
nance and lubrication chart. In addition,
the condition of the spark plug can re-
veal the condition of the engine.
To remove the spark plug
1. Remove the spark plug cap.
2. Remove the spark plug as shown,
with the spark plug wrench includ-
ed in the owner’s tool kit.
1. Screw
1
1. Spark plug cap
11
U27SE0E0.book Page 7 Friday, February 22, 2008 8:54 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-8
6To check the spark plug
1. Check that the porcelain insulator
around the center electrode of the
spark plug is a medium-to-light tan
(the ideal color when the vehicle is
ridden normally).
NOTE:
If the spark plug shows a distinctly dif-
ferent color, the engine could be oper-
ating improperly. Do not attempt to
diagnose such problems yourself. In-
stead, have a Yamaha dealer checkthe vehicle.2. Check the spark plug for electrode
erosion and excessive carbon or
other deposits, and replace it if
necessary.
To install the spark plug
1. Measure the spark plug gap with a
wire thickness gauge and, if nec-
essary, adjust the gap to specifica-
tion.2. Clean the surface of the spark plug
gasket and its mating surface, and
then wipe off any grime from the
spark plug threads.
3. Install the spark plug with the
spark plug wrench, and then tight-
en it to the specified torque.
NOTE:
If a torque wrench is not available when
installing a spark plug, a good estimate
of the correct torque is 1/4–1/2 turn
past finger tight. However, the spark
plug should be tightened to the speci-fied torque as soon as possible.
4. Install the spark plug cap.
1. Spark plug wrench
Specified spark plug:
NGK/CR6HSA1. Spark plug gapSpark plug gap:
0.6–0.7 mm (0.024–0.028 in)
Tightening torque:
Spark plug:
12.5 Nm (1.25 m·kgf, 9.0 ft·lbf)
U27SE0E0.book Page 8 Friday, February 22, 2008 8:54 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-9
6
EAU37171
Engine oil The engine oil level should be checked
before each ride. In addition, the oil
must be changed at the intervals spec-
ified in the periodic maintenance and
lubrication chart.
To check the engine oil level
1. Place the vehicle on the center-
stand.NOTE:Make sure that the vehicle is positioned
straight up when checking the oil level.
A slight tilt to the side can result in afalse reading.
2. Start the engine, warm it up for
several minutes, and then turn it
off.
3. Wait a few minutes until the oil set-
tles, remove the oil filler cap, wipe
the dipstick clean, insert it back
into the oil filler hole (without
screwing it in), and then remove it
again to check the oil level.
NOTE:
The engine oil should be between theminimum and maximum level marks.4. If the engine oil is at or below the
minimum level mark, add sufficient
oil of the recommended type to
raise it to the correct level.
5. Insert the dipstick into the oil filler
hole, and then tighten the oil filler
cap.
To change the engine oil
1. Start the engine, warm it up for
several minutes, and then turn it
off.
2. Place an oil pan under the engine
to collect the used oil.
3. Remove the engine oil filler cap
and drain bolt to drain the oil from
the crankcase.1. Engine oil filler cap
1. Dipstick
2. Maximum level mark
3. Minimum level mark
1. Engine oil drain bolt
2. Oil pan
U27SE0E0.book Page 9 Friday, February 22, 2008 8:54 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-10
64. Install the engine oil drain bolt, and
then tighten it to the specified
torque.
5. Refill with the specified amount of
the recommended engine oil, and
then install and tighten the engine
oil filler cap.
CAUTION:
ECA11620


In order to prevent clutch slip-
page (since the engine oil also
lubricates the clutch), do not
mix any chemical additives. Do
not use oils with a diesel speci-
fication of “CD” or oils of a high-
er quality than specified. In
addition, do not use oils labeled
“ENERGY CONSERVING II” or
higher.


Make sure that no foreign mate-rial enters the crankcase.
6. Start the engine, and then let it idle
for several minutes while checking
it for oil leakage. If oil is leaking, im-
mediately turn the engine off and
check for the cause.
7. Turn the engine off, and then
check the oil level and correct it if
necessary.
EAU37121
Cleaning the air filter element The air filter element should be cleaned
at the intervals specified in the periodic
maintenance and lubrication chart.
Clean the air filter element more fre-
quently if you are riding in unusually
wet or dusty areas.
1. Remove panel B. (See page 6-6.)
2. Remove the air filter case cover by
removing the screws.
3. Remove the air filter element.
Tightening torque:
Engine oil drain bolt:
20 Nm (2.0 m·kgf, 14 ft·lbf)
Recommended engine oil:
See page 8-1.
Oil change quantity:
1.00 L (1.06 US qt, 0.88 Imp.qt)
1.“CD” specification
2.“ENERGY CONSERVING II”
1
2
1. Screw
2. Air filter case cover
2
11
U27SE0E0.book Page 10 Friday, February 22, 2008 8:54 AM