2003 YAMAHA TTR125 light

ILLUSTRATED SYMBOLS
(Refer to the illustration)
Illustrated symbols
1
to
6
are designed as
thumb tabs to indicate the chapter’s number
and content.
1
General information
2
Specifications
3
Regular inspection and adjustments
4
Engine
5
Chassis
6
Electrical
Illustrated symbols
7
to
D
are used to identify
the specifications appearing in the text.
7
With engine mounted
8
Special tool
9
Filling fluid
0
Lubricant
ATightening
BSpecified value, Service limit
CEngine speed
DResistance (Ω), Voltage (V), Electric current (A)
Illustrated symbols E to H in the exploded
diagrams indicate grade of lubricant and loca-
tion of lubrication point.
EApply engine oil
FApply molybdenum disulfide oil
GApply lightweight lithium-soap base grease
HApply molybdenum disulfide grease
Illustrated symbols I to J in the exploded
diagrams indicate where to apply a locking
agent and when to install new parts.
IApply locking agent (LOCTITE®)
JUse new one 12
34
56
78
90
AB
CD
EF
GH
IJ
GEN
INFOSPEC
INSP
ADJENG
CHAS–+ELEC
T R..
EM
LSM
LTNew

1 - 1
GEN
INFO

DESCRIPTION
EC100000
GENERAL INFORMATION
EC110000
DESCRIPTION
1
Clutch lever
2
Engine stop switch
3
Main switch
4
Starter knob
5
Start switch
6
Front brake lever
7
Throttle grip
8
Fuel tank cap
9
Air filter
0
Kickstarter crank
A
Fuel tank
B
Dipstick
C
Rear brake pedal
D
Fuel cock
E
Drive chain
F
Shift pedal
G
Front fork
*The illustration shows the TT-R125LWE.
NOTE:


The machine you have purchased may differ
slightly from those shown in the following.

Designs and specifications are subject to
change without notice.
90A
CB
D
FE G
12 34 5 6
7 8

1 - 4
GEN
INFO

IMPORTANT INFORMATION
EC132000
ALL REPLACEMENT PARTS
1. We recommend to use Yamaha genuine
parts for all replacements. Use oil and/or
grease recommended by Yamaha for
assembly and adjustment.
EC133000
GASKETS, OIL SEALS AND O-RINGS
1. All gaskets, oil seals, and O-rings should
be replaced when an engine is over-
hauled. All gasket surfaces, oil seal lips,
and O-rings must be cleaned.
2. Properly oil all mating parts and bearings
during reassembly. Apply grease to the
oil seal lips.
EC134000
LOCK WASHERS/PLATES AND COTTER
PINS
1. All lock washers/plates
1
and cotter pins
must be replaced when they are
removed. Lock tab(s) should be bent
along the bolt or nut flat(s) after the bolt
or nut has been properly tightened.
EC135001
BEARINGS AND OIL SEALS
1. Install the bearing(s)
1
and oil seal(s)
2
with their manufacturer’s marks or num-
bers facing outward. (In other words, the
stamped letters must be on the side
exposed to view.) When installing oil
seal(s), apply a light coating of light-
weight lithium base grease to the seal
lip(s). Oil the bearings liberally when
installing.
CAUTION:

Do not use compressed air to spin the
bearings dry. This causes damage to the
bearing surfaces.
EC136000
CIRCLIPS
1. All circlips should be inspected carefully
before reassembly. Always replace pis-
ton pin clips after one use. Replace dis-
torted circlips. When installing a circlip
1
,
make sure that the sharp-edged corner
2
is positioned opposite to the thrust
3
it
receives. See the sectional view.
4
Shaft

1 - 10
GEN
INFO
CONTROL FUNCTIONS
KICKSTARTER CRANK
WARNING
Before starting the engine, be sure to shift
the transmission into neutral.
Rotate the kickstarter crank 1 away from the
engine. Push the starter down lightly with your
foot until the gears engage, then kick smoothly
and forcefully to start the engine.
EC155001
THROTTLE GRIP
The throttle grip 1 is located on the right han-
dlebar; it accelerates or decelerates the
engine. For acceleration, turn the grip toward
you; for deceleration, turn it away from you.
EC156000
FRONT BRAKE LEVER
The front brake lever 1 is located on the right
handlebar. Pull it toward the handlebar to acti-
vate the front brake.
EC157000
REAR BRAKE PEDAL
The rear brake pedal 1 is located on the right
side of the machine. Press down on the brake
pedal to activate the rear brake.

1 - 13
GEN
INFO
STARTING AND BREAK-IN
EC190000
STARTING AND BREAK-IN
CAUTION:
Before starting the machine, perform the
checks in the pre-operation check list.
WARNING
Never start or run the engine in a closed
area. The exhaust fumes are poisonous;
they can cause loss of consciousness and
death in a very short time. Always operate
the machine in a well-ventilated area.
STARTING A COLD ENGINE
NOTE:
This model is equipped with an ignition circuit
cut-off system. The engine can be started
under the following conditions.
When the transmission is in neutral.
When the clutch is disengaged with the
transmission in any position. However, it is
recommended to shift into neutral before
starting the engine.
1. Shift the transmission into neutral.
2. Turn the fuel cock to “ON” and full open
the starter knob (CHOKE).
3. Turn the main switch to “ON”.
4. With the throttle completely closed start
the engine by pushing the start switch or
by kicking the kickstarter crank forcefully
with firm stroke.
5. Run the engine at idle or slightly higher
until it warms up: this usually takes about
one or two minutes.
6. The engine is warmed up when it
responds normally to the throttle with the
starter knob (CHOKE) turned off.

1 - 14
GEN
INFO
NOTE:
If the engine fails to start by pushing the start
switch, release the switch, 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 using
the kickstarter.
CAUTION:
Do not warm up the engine for extended
periods.
EC193001
STARTING A WARM ENGINE
Do not operate the starter knob (CHOKE).
Open the throttle slightly and start the engine
by kicking the kickstater forcefully with firm
stroke.
CAUTION:
Observe the following break-in procedures
during initial operation to ensure optimum
performance and avoid engine damage.
BREAK-IN
Break-in is important to better fit the moving
and sliding parts as well as the installed parts.
It is also important to accustom the rider to the
machine better.
Avoid full-throttle run on a new machine for the
first 5 hours.
After the trial run, check for loose parts, oil
leakage and other problems.
Make full inspection and adjustment especially
of slack cables and drive chain and loose
spokes.
CAUTION:
After the break-in or before each ride, you
must check the entire machine for loose fit-
tings and fasteners as per “TORQUE-
CHECK POINTS”.
Tighten all such fasteners as required.
STARTING AND BREAK-IN

1 - 19
GEN
INFO
CLEANING AND STORAGE
EC182001
STORAGE
If your machine is to be stored for 60 days or
more, some preventive measures must be
taken to avoid deterioration. After cleaning the
machine thoroughly, prepare it for storage as
follows:
1. Drain the fuel tank, fuel lines, and the car-
buretor float bowl.
2. Remove the spark plug, pour a table-
spoon of SAE 10W-30 motor oil in the
spark plug hole, and reinstall the plug.
With the engine stop switch pushed in,
kick the engine over several times to coat
the cylinder walls with oil.
3. Remove the drive chain, clean it thor-
oughly with solvent, and lubricate it. Rein-
stall the chain or store it in a plastic bag
tied to the frame.
4. Lubricate all control cables.
5. Block the frame up to raise the wheels off
the ground.
6. Tie a plastic bag over the exhaust pipe
outlet to prevent moisture from entering.
7. If the machine is to be stored in a humid
or salt-air environment, coat all exposed
metal surfaces with a film of light oil. Do
not apply oil to rubber parts or the seat
cover.
NOTE:
Make any necessary repairs before the
machine is stored.

SPEC
2 - 23
MAINTENANCE SPECIFICATIONS
EC212300
ELECTRICAL
Item Standard Limit
CDI:
Magneto-model/manufacturer 5HP-10/YAMAHA ----
Source coil resistance (color) 688 ~ 1,032 Ω at 20 ˚C (68 ˚F)
(Brown – Green)----
Pickup coil resistance (color) 248 ~ 372 Ω at 20 ˚C (68 ˚F)
(Red – White)----
CDI unit-model/manufacturer 5HP-00/YAMAHA ----
Ignition coil:
Model/manufacturer 4KJ-10/YAMAHA ----
Minimum spark gap 6 mm (0.24 in) ----
Primary winding resistance 0.18 ~ 0.28 Ω at 20 ˚C (68 ˚F) ----
Secondary winding resistance 6.3 ~ 9.5 kΩ at 20 ˚C (68 ˚F) ----
Spark plug cap:
Type Resin ----
Resistance 10 kΩ at 20 ˚C (68 ˚F) ----
Charging system:
System type CDI magneto ----
Model/manufacturer 5HP-10/YAMAHA ----
Normal output 14 V/100 W at 5,000 r/min ----
Charging coil resistance (color) 0.64 ~ 0.96 Ω at 20 ˚C (68 ˚F)
(White – Black)----
Lighting coil resistance (color) 0.52 ~ 0.78 Ω at 20 ˚C (68 ˚F)
(Yellow – Black)----
Rectifier/regulator:
Regulator type Semiconductor short circuit ----
Model/manufacture SH620B-12/SHINDENGEN ----
No-load regulated voltage 14.0 ~ 15.0 V ----
Rectifier capacity 8 A ----
Electric starting system:
Type Constant mesh
Starter motor:
Model/manufacturer 5HP00/YAMAHA ----
Operation voltage 12 V ----
Output 0.25 kW ----
Armature coil resistance 0.017 ~ 0.021 Ω at 20 ˚C (68 ˚F) ----
Brush overall length 10 mm (0.40 in) 3.5 mm
(0.14 in)
Brush quantity 2 pcs. ----
Spring force 5.52 ~ 8.28 N
(560 ~ 840 g, 19.8 ~ 29.7 oz)----
Commutator diameter 22 mm (0.9 in) 21 mm
(0.8 in)
Mica undercut (depth) 1.5 mm (0.06 in) ----