2008 YAMAHA YZF-R125 transmission

INSTRUMENT AND CONTROL FUNCTIONS
3-2
3
EAU11003
Indicator and warning lights
EAU11020
Turn signal indicator light“”
This indicator light flashes when the
turn signal switch is pushed to the left or
right.
EAU11060
Neutral indicator light“”
This indicator light comes on when the
transmission is in the neutral position.
EAU11080
High beam indicator light“”
This indicator light comes on when the
high beam of the headlight is switched
on.
EAUM2290
Coolant temperature warning
light“”
This warning light comes on when the
engine overheats. When this occurs,
stop the engine immediately and allow
the engine to cool.
The electrical circuit of the warning light
can be checked by turning the key to
“ON”.
If the warning light does not come on
for a few seconds, then go off, have a
Yamaha dealer check the electrical cir-
cuit.CAUTION:
ECA10020
Do not operate the engine if it isoverheated.
EAU11500
Engine trouble warning light“”
This warning light comes on or flashes
when an electrical circuit monitoring the
engine is defective. When this occurs,
have a Yamaha dealer check the self-
diagnosis system.
The electrical circuit of the warning light
can be checked by turning the key to
“ON”. If the warning light does not come
on for a few seconds, then go off, have
a Yamaha dealer check the electrical
circuit.
1. Neutral indicator light“”
2. Turn signal indicator light“”
3. High beam indicator light“”
4. Engine trouble warning light“”
5. Coolant temperature warning light“”U5D7E0E0.book Page 2 Tuesday, December 18, 2007 10:13 AM

INSTRUMENT AND CONTROL FUNCTIONS
3-6
3
EAU12870
Shift pedal The shift pedal is located on the left
side of the engine and is used in com-
bination with the clutch lever when
shifting the gears of the 6-speed con-
stant-mesh transmission equipped on
this motorcycle.
EAU12890
Brake lever The brake lever is located at the right
handlebar grip. To apply the front
brake, pull the lever toward the handle-
bar grip.
EAU12941
Brake pedal The brake pedal is on the right side of
the motorcycle. To apply the rear
brake, press down on the brake pedal.
1. Shift pedal
1. Brake lever
1. Brake pedal
U5D7E0E0.book Page 6 Tuesday, December 18, 2007 10:13 AM

INSTRUMENT AND CONTROL FUNCTIONS
3-10
3
EAU15301
Sidestand The sidestand is located on the left side
of the frame. Raise the sidestand or
lower it with your foot while holding the
vehicle upright.NOTE:The built-in sidestand switch is part of
the ignition circuit cut-off system, which
cuts the ignition in certain situations.
(See further down for an explanation ofthe ignition circuit cut-off system.)
WARNING
EWA10240
The vehicle must not be ridden with
the sidestand down, or if the side-
stand cannot be properly moved up
(or does not stay up), otherwise the
sidestand could contact the ground
and distract the operator, resulting
in a possible loss of control.
Yamaha’s ignition circuit cut-off
system has been designed to assist
the operator in fulfilling the respon-
sibility of raising the sidestand be-
fore starting off. Therefore, check
this system regularly as describedbelow and have a Yamaha dealer re-
pair it if it does not function proper-
ly.
EAU44890
Ignition circuit cut-off system The ignition circuit cut-off system (com-
prising the sidestand switch, clutch
switch and neutral switch) has the fol-
lowing functions.

It prevents starting when the trans-
mission is in gear and the side-
stand is up, but the clutch lever is
not pulled.


It prevents starting when the trans-
mission is in gear and the clutch le-
ver is pulled, but the sidestand is
still down.


It cuts the running engine when the
transmission is in gear and the sid-
estand is moved down.
Periodically check the operation of the
ignition circuit cut-off system according
to the following procedure.WARNING
EWA10250
If a malfunction is noted, have a
Yamaha dealer check the system be-fore riding.
U5D7E0E0.book Page 10 Tuesday, December 18, 2007 10:13 AM

INSTRUMENT AND CONTROL FUNCTIONS
3-11
3
With the engine turned off:
1. Move the sidestand down.
2. Make sure that the engine stop switch is turned on.
3. Turn the key on.
4. Shift the transmission into the neutral position.
5. Push the start switch.
Does the engine start?
With the engine still running:
6. Move the sidestand up.
7. Keep the clutch lever pulled.
8. Shift the transmission into gear.
9. Move the sidestand down.
Does the engine stall?
After the engine has stalled:
10. Move the sidestand up.
11. Keep the clutch lever pulled.
12. Push the start switch.
Does the engine start?
The system is OK. The motorcycle can be ridden.The neutral switch may be defective.
The motorcycle should not be ridden until
checked by a Yamaha dealer.
The sidestand switch may be defective.
The motorcycle should not be ridden until
checked by a Yamaha dealer.
The clutch switch may be defective.
The motorcycle should not be ridden until
checked by a Yamaha dealer.
YES NO YES NO YES NO
U5D7E0E0.book Page 11 Tuesday, December 18, 2007 10:13 AM

OPERATION AND IMPORTANT RIDING POINTS
5-1
5
EAU15950
WARNING
EWA10270


Become thoroughly familiar
with all operating controls and
their functions before riding.
Consult a Yamaha dealer re-
garding any control or function
that you do not thoroughly un-
derstand.


Never start the engine or oper-
ate it in a closed area for any
length of time. Exhaust fumes
are poisonous, and inhaling
them can cause loss of con-
sciousness and death within a
short time. Always make sure
that there is adequate ventila-
tion.


Before starting out, make sure
that the sidestand is up. If the
sidestand is not raised com-
pletely, it could contact the
ground and distract the opera-
tor, resulting in a possible lossof control.
EAUM2320
Starting the engine In order for the ignition circuit cut-off
system to enable starting, one of the
following conditions must be met:

The transmission is in the neutral
position.


The transmission is in gear with
the clutch lever pulled and the sid-
estand up.WARNING
EWA10290


Before starting the engine,
check the function of the igni-
tion circuit cut-off system ac-
cording to the procedure
described on page 3-10.


Never ride with the sidestanddown.
1. Turn the key to “ON” and make
sure that the engine stop switch is
set to“”.
CAUTION:
ECAM1100
The following warning lights and in-
dicator light should come on for a
few seconds, then go off.

Neutral indicator light


Turn signal indicator light


High beam indicator light


Coolant temperature warning
light


Engine trouble warning light
If a warning or indicator light does
not go off, see page 3-2 for the corre-
sponding warning and indicator
light circuit check.
2. Shift the transmission into the neu-
tral position.NOTE:When the transmission is in the neutral
position, the neutral indicator light
should be on, otherwise have a
Yamaha dealer check the electrical cir-cuit.
3. Start the engine by pushing the
start switch.NOTE:If the engine fails to start, release the
start switch, wait a few seconds, and
then try again. Each starting attempt
should be as short as possible to pre-
serve the battery. Do not crank the en-
gine more than 10 seconds on any oneattempt.
U5D7E0E0.book Page 1 Tuesday, December 18, 2007 10:13 AM

OPERATION AND IMPORTANT RIDING POINTS
5-2
5
CAUTION:
ECA11040
For maximum engine life, never ac-
celerate hard when the engine iscold!NOTE:The engine is warm when it quickly re-sponds to the throttle.
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.
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.
1. Shift pedal
2. Neutral position
U5D7E0E0.book Page 2 Tuesday, December 18, 2007 10:13 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-22
6


Be careful that water does not en-
ter the brake fluid reservoir when
refilling. Water will significantly
lower the boiling point of the fluid
and may result in vapor lock.


Brake fluid may deteriorate paint-
ed surfaces or plastic parts. Al-
ways clean up spilled fluid
immediately.


As the brake pads wear, it is nor-
mal for the brake fluid level to grad-
ually go down. However, if the
brake fluid level goes down sud-
denly, have a Yamaha dealer
check the cause.
EAUM1360
Changing the brake fluid Have a Yamaha dealer change the
brake fluid at the intervals specified in
the periodic maintenance and lubrica-
tion chart. In addition, have the brake
hose replaced every four years or
whenever it is damaged or leaking.
EAU22760
Drive chain slack The drive chain slack should be
checked before each ride and adjusted
if necessary.
EAU22773
To check the drive chain slack
1. Place the motorcycle on the side-
stand.NOTE:When checking and adjusting the drive
chain slack, there should be no weighton the motorcycle.
2. Shift the transmission into the neu-
tral position.
3. Move the rear wheel by pushing
the motorcycle to locate the tight-
est portion of the drive chain, and
then measure the drive chain slack
as shown.Drive chain slack:
30.0–40.0 mm (1.18–1.57 in)
U5D7E0E0.book Page 22 Tuesday, December 18, 2007 10:13 AM

SPECIFICATIONS
8-1
8
Dimensions:Overall length:
2015 mm (79.3 in)
Overall width:
660 mm (26.0 in)
Overall height:
1065 mm (41.9 in)
Seat height:
818 mm (32.2 in)
Wheelbase:
1355 mm (53.3 in)
Ground clearance:
155 mm (6.10 in)
Minimum turning radius:
3100 mm (122.0 in)Weight:With oil and fuel:
138.0 kg (304 lb)Engine:Engine type:
Liquid cooled 4-stroke, SOHC
Cylinder arrangement:
Forward-inclined single cylinder
Displacement:
124.7 cm³
Bore × stroke:
52.0 × 58.6 mm (2.05 × 2.31 in)
Compression ratio:
11.20 :1
Starting system:
Electric starter
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:
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)Cooling system:Coolant reservoir capacity (up to the
maximum level mark):
0.25 L (0.26 US qt) (0.22 Imp.qt)
Radiator capacity (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 only
Fuel tank capacity:
13.8 L (3.65 US gal) (3.04 Imp.gal)
Fuel reserve amount:
1.6 L (0.42 US gal) (0.35 Imp.gal)Fuel injection:Throttle body:
Manufacturer:
MIKUNI
Type/quantity:
SE AC28-2/1Spark plug (s):Manufacturer/model:
NGK/CR8E
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)Clutch:Clutch type:
Wet, multiple-discTransmission:Primary reduction system:
Helical gear
Primary reduction ratio:
73/24 (3.042)
Secondary reduction system:
Chain drive
Secondary reduction ratio:
48/14 (3.429)
Transmission type:
Constant mesh 6-speed
Operation:
Left foot operation
-20 -10 0
10 20 30
40
50 ˚C
SAE 10W-30
SAE 15W-40SAE 20W-40SAE 20W-50
SAE 10W-40SAE 10W-50
U5D7E0E0.book Page 1 Tuesday, December 18, 2007 10:13 AM