2003 YAMAHA TTR125 check engine

IMPORTANT NOTICE
This machine is designed for off-road use only
by young operators under adult instruction and
supervision. It is illegal for this machine to be
operated on any public street, road, or high-
way.
Off-road use on public lands may be illegal.
Please check local regulations before riding.
1. GASOLINE IS HIGHLY FLAMMABLE:
* Always turn off the engine when
refueling.
* Take care not to spill on the engine
or exhaust pipe/muffler, when refu-
eling.
* Never refuel while smoking or in
the vicinity of an open flame.
2. If you should swallow some gasoline
or inhale a lot of gasoline vapor, or
allow some gasoline to get in your
eye(s), see your doctor immediately.
If any gasoline spills on your skin or
clothing, immediately wash it with
soap and water, and change your
clothes.
3. Always turn off the engine before
leaving the machine unattended.
When parking the machine, note the
following:
* The engine and exhaust pipe(s)/
muffler(s) may be hot. Park the
machine in a place where pedestri-
ans or children are not likely to
touch the machine.
* Do not park the machine on a slope
or soft ground; the machine may
overturn.
SAFETY INFORMATION

6. When going for riding, be sure to be with
your family.
Never go alone.
7. Before riding the machine, ask your par-
ents to check the machine very carefully.
8. Do not touch the areas shown, or you will
get burnt in the hand.
9. Do not touch rotating or moving parts.
10. Before starting the engine, be sure to shift
the transmission into neutral.

EC0A0000
CONTENTS
CHAPTER 1
GENERAL INFORMATION
DESCRIPTION
...........................................1-1
MACHINE IDENTIFICATION
.....................1-2
IMPORTANT INFORMATION
....................1-3
CHECKING OF CONNECTION
.................1-5
SPECIAL TOOLS
......................................1-6
CONTROL FUNCTIONS
............................1-9
FUEL
........................................................1-12
STARTING AND BREAK-IN
....................1-13
TORQUE-CHECK POINTS
......................1-16
TT-R125E
............................................1-16
TT-R125LWE
.......................................1-17
CLEANING AND STORAGE
...................1-18
CHAPTER 2
SPECIFICATIONS
GENERAL SPECIFICATIONS
....................2-1
TT-R125E
..............................................2-1
TT-R125LWE
.........................................2-4
MAINTENANCE SPECIFICATIONS
..........2-7
ENGINE
....................................................2-7
CHASSIS
................................................2-15
TT-R125E
............................................2-15
TT-R125LWE
.......................................2-19
ELECTRICAL
.........................................2-23
GENERAL TORQUE
SPECIFICATIONS
...................................2-25
DEFINITION OF UNITS
...........................2-25
CABLE ROUTING DIAGRAM
.................2-26
CHAPTER 3
REGULAR INSPECTION AND
ADJUSTMENTS
MAINTENANCE INTERVALS
...................3-1
PRE-OPERATION INSPECTION
AND MAINTENANCE
................................3-3
ENGINE
......................................................3-4
CHASSIS
.................................................3-15
ELECTRICAL
...........................................3-32

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 - 15
GEN
INFO
STARTING AND BREAK-IN
BREAKING IN AFTER REPLACEMENT
After a part is replaced with a new one, it is
necessary to break it in as in a new machine.
This is required especially when the following
engine-related parts are replaced.
Cylinder
Piston
Piston ring
Valve
Camshaft
Crankshaft
Clutch
Transmission gear
Shift fork
* For warming up and inspection during
break-in, refer to “GENERAL INSPECTION
AND MAINTENANCE” section in the
CHAPTER 3 and if there is any problem,
stop the engine immediately and check.

1 - 16
GEN
INFO
TORQUE-CHECK POINTS
TORQUE-CHECK POINTS
TT-R125E
Engine mounting
Muffler
Steering Steering stem to
handlebar
Suspension Front Steering stem to
front fork
Rear For link type
Rear Installation of shock
absorber
Rear Installation of swing-
arm
Wheel Installation of wheel Front
Rear
Brake Front
Rear
Fuel systemFrame to engine
Frame to engine bracket
Engine bracket to engine
Muffler to cylinder head
Muffler to rear fender bracket
Muffler to seat pillar tube
Steering stem to frame
Steering stem to upper bracket
Upper bracket to handlebar
Front fork to upper bracket
Front fork to lower bracket
Assembly of links
Link to frame
Link to shock absorber
Link to swingarm
Shock absorber to frame
Tightening of pivot shaft
Tightening of wheel axle
Tightening of wheel axle
Wheel to sprocket
Camshaft lever to camshaft
Camshaft lever to camshaft
Fuel tank to fuel cock
NOTE:
Concerning the tightening torque, refer to
“MAINTENANCE SPECIFICATIONS” section
in the CHAPTER 2.

1 - 17
GEN
INFO
TORQUE-CHECK POINTS
TT-R125LWE
Engine mounting
Muffler
Steering Steering stem to
handlebar
Suspension Front Steering stem to
front fork
Rear For link type
Rear Installation of shock
absorber
Rear Installation of swing-
arm
Wheel Installation of wheel Front
Rear
Brake Front
Rear
Fuel systemFrame to engine
Frame to engine bracket
Engine bracket to engine
Muffler to cylinder head
Muffler to rear fender bracket
Muffler to seat pillar tube
Steering stem to frame
Steering stem to upper bracket
Upper bracket to handlebar
Front fork to upper bracket
Front fork to lower bracket
Assembly of links
Link to frame
Link to shock absorber
Link to swingarm
Shock absorber to frame
Tightening of pivot shaft
Tightening of wheel axle
Tightening of wheel axle
Wheel to sprocket
Brake caliper to front fork
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to joint
Brake hose to joint
Brake master cylinder to handlebar
Tightening of bleed screw
Brake camshaft lever to brake camshaft
Fuel tank to fuel cock
NOTE:
Concerning the tightening torque, refer to
“MAINTENANCE SPECIFICATIONS” section
in the CHAPTER 2.