engine assembly YAMAHA TTR125 2005 Owners Manual

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.
4Shaft

1 - 16
GEN
INFO
TORQUE-CHECK POINTS
TORQUE-CHECK POINTS
TT-R125/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 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-R125LW/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 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.

SPEC
2 - 13
MAINTENANCE SPECIFICATIONS
Part to be tightened Thread size Q’tyTightening torque
Nm m•kg ft•lb
Spark plug M10 × 1.0 1 13 1.3 9.4
Cylinder head bolt M8 × 1.25 4 22 2.2 16
Cylinder head bolt M6 × 1.0 2 10 1.0 7.2
Oil pressure check bolt M6 × 1.0 1 7 0.7 5.1
Cylinder head side cover M6 × 1.0 2 10 1.0 7.2
Tappet cover M45 × 1.5 2 18 1.8 13
Timing chain guide M6 × 1.0 1 10 1.0 7.2
Adjusting screw (valve) and locknut M5 × 0.5 2 8 0.8 5.8
Camshaft sprocket M8 × 1.25 1 20 2.0 14
Bearing plate cover (camshaft) M6 × 1.0 1 10 1.0 7.2
Timing chain tensioner cap bolt M6 × 1.0 1 8 0.8 5.8
Timing chain tensioner M6 × 1.0 2 10 1.0 7.2
Oil pump assembly M6 × 1.0 2 7 0.7 5.1
Oil pump cover M5 × 0.8 1 5 0.5 3.6
Engine oil drain bolt M12 × 1.5 1 20 2.0 14
Carburetor joint M6 × 1.0 2 10 1.0 7.2
Carburetor joint clamp (air filter) M4 × 0.7 1 2 0.2 1.4
Coasting enricher cover M4 × 0.7 2 2 0.2 1.4
Air filter case M6 × 1.0 3 7 0.7 5.1
Muffler M6 × 1.0 2 10 1.0 7.2
Muffler M10 × 1.25 1 60 6.0 43
Muffler M8 × 1.25 1 30 3.0 22
Muffler guard M6 × 1.0 7 10 1.0 7.2
Spark arrester M6 × 1.0 3 10 1.0 7.2
Crankcase M6 × 1.0 10 10 1.0 7.2
Left crankcase cover M6 × 1.0 7 10 1.0 7.2
Drive sprocket cover M6 × 1.0 2 12 1.2 8.7
Right crankcase cover M6 × 1.0 9 10 1.0 7.2
Lead guide (CDI magneto lead) M6 × 1.0 1 7 0.7 5.1
Timing mark accessing screw M14 × 1.5 1 7 0.7 5.1
Crankshaft end accessing screw M32 × 1.5 1 7 0.7 5.1
Kickstarter crank M12 × 1.0 1 50 5.0 36
Starter clutch (TT-R125E/TT-R125LWE) M8 × 1.25 3 30 3.0 22
Plate (starter idle gear) (TT-R125E/TT-R125LWE) M6 × 1.0 2 7 0.7 5.1
Primary drive gear M12 × 1.0 1 70 7.0 50
Clutch spring M5 × 0.8 4 6 0.6 4.3
Clutch boss M12 × 1.0 1 60 6.0 43
Adjusting screw (push rod) and locknut M6 × 1.0 1 8 0.8 5.8
Bearing plate cover (main axle) M6 × 1.0 2 7 0.7 5.1
Drive sprocket M5 × 0.8 2 6 0.6 4.3
Shift arm M6 × 1.0 1 10 1.0 7.2
Shift rod and shift pedal M6 × 1.0 1 7 0.7 5.1
Shift rod and shift arm M6 × 1.0 1 7 0.7 5.1
Shift pedal M6 × 1.0 1 12 1.2 8.7

SPEC
2 - 22
MAINTENANCE SPECIFICATIONS
NOTE:
- marked portion shall be checked for torque tightening after break-in o\
r before each ride.Part to be tightened Thread size Q
’ty Tightening torque
Nm m •kg ft •lb
Bead stopper M8 × 1.25 1 3 0.3 2.2
Driven sprocket (nut) M10 × 1.25 4 43 4.3 31
Driven sprocket (stud) M10 × 1.25 4 30 3.0 22
Sidestand mounting (nut) M10 × 1.25 1 44 4.4 32
Engine mounting: Engine bracket (front) and frame M8 × 1.25 2 40 4.0 29
Engine bracket (front) and engine M8 × 1.25 2 40 4.0 29
Engine bracket (upper) and frame M8 × 1.25 2 40 4.0 29
Engine bracket (upper) and cylinder head M8 × 1.25 1 40 4.0 29
Engine and frame (rear) M8 × 1.25 2 40 4.0 29
Pivot shaft and nut M12 × 1.25 1 53 5.3 38
Relay arm and swingarm (TT-R125LW) M12 × 1.25 1 70 7.0 50
(TT-R125LWE) M12 × 1.25 1 53 5.3 38
Relay arm and connecting arm M10 × 1.25 1 35 3.5 25
Connecting arm and frame M10 × 1.25 1 35 3.5 25
Rear shock absorber assembly and frame M12 × 1.25 1 53 5.3 38
Rear shock absorber assembly and relay arm M10 × 1.25 1 35 3.5 25
Rear shock absorber and locknut (preload) M46 × 1.5 1 42 4.2 30
Drive chain tensioner (upper) M8 × 1.25 1 23 2.3 17
Drive chain tensioner (lower) M6 × 1.0 1 7 0.7 5.1
Drive chain support and swingarm M6 × 1.0 2 7 0.7 5.1
Drive chain guide and swingarm M6 × 1.0 2 7 0.7 5.1
Drive chain guard mounting M6 × 1.0 2 7 0.7 5.1
Fuel tank mounting M6 × 1.0 2 10 1.0 7.2
Fuel tank and fuel cock M6 × 1.0 2 7 0.7 5.1
Fuel tank and fuel tank bracket M6 × 1.0 4 7 0.7 5.1
Front fender mounting M6 × 1.0 4 7 0.7 5.1
Rear fender mounting M6 × 1.0 4 7 0.7 5.1
Flap guard mounting M6 × 1.0 2 4 0.4 2.9
Left side cover mounting M6 × 1.0 2 7 0.7 5.1
Seat mounting M6 × 1.0 2 7 0.7 5.1
Battery cover and battery box (TT-R125LWE) M6 × 1.0 1 5 0.5 3.6
Battery box and frame (TT-R125LWE) M6 × 1.0 1 7 0.7 5.1

2 - 30
SPECCABLE ROUTING DIAGRAM
TT-R125E/TT-R125LWE
1Ground lead
2Primary coil lead
3Clamp
4Wire harness
5Starter relay lead
6Rectifier/regulator lead
7CDI magneto lead
8Air vent hose
9Neutral switch lead
0Rear shock absorber assembly
sub-tank hose (TT-R125LWE
only)
AStarting circuit cut-off relay lead
BCDI unit lead
CCorrugated tubeDBrake hose holder (Brake cable
holder for the TT-R125E)
EBrake hose (Brake cable for the
TT-R125E)
FCable guide
GMain switch lead
HEngine stop switch lead
IClutch switch lead
JStart switch lead
KCDI unit band
LCDI unit
MConnector cover
NRubber cover
OStarter cable
PThrottle cableQRectifier/regulator
ÅFasten the primary coil lead and
ground lead.
ıFasten the wire harness at its
tape.
ÇFasten the wire harness and
CDI magneto lead in front of the
rear shock absorber assembly
bracket at the protecting tube
for the CDI magneto lead.
30~35 mm
(1.18~1.38 in)
E
DD
A
C
B-B
D-D
E
B
BC
TT-R125EA
L
1
3
4 2
3
35
3
36
7
3
3
8
9 0 A 3 B C
DEFGHIJKOP
7
4
0
3 3M
N
3Q
3 F
E
DË
◊
„
Ù
AB
AA
Û
ÁAC
N
Ì
Ï ‰ Î
Ç ı Å
Ó
È
Ô

Ò ˜ ˆ Ø ∏
ŒÂÍ ÊÂ

2 - 31
SPECCABLE ROUTING DIAGRAM
ÎAfter fastening the starter relay
lead, pass it on the left of the
chassis.
‰Fasten the CDI magneto lead
and starter relay lead.
ÏFasten the wire harness.
ÌPass the rectifier/regulator lead
between the frame and air filter
case.
ÓDo not allow the CDI magneto
lead to slacken except between
the two plastic locking ties.
ÈFasten the CDI magneto lead
over the engine bracket (rear).
ÔFasten the CDI magneto lead.Pass the air vent hoses between
the engine and swingarm.
ÒFit the neutral switch lead into
the groove in the crankcase
cover.
˜Pass the starting circuit cut-off
relay lead under the frame and
at the right of the chassis.
ˆFasten the rear shock absorber
assembly sub-tank.
(TT-R125LWE only)
ØPass the CDI unit lead on the
outside of the main switch lead,
engine stop switch lead, clutch
switch lead and start switch
lead.∏After fastening the start switch
lead, clutch switch lead, engine
stop switch lead and main
switch lead, push their corru-
gated tube against the CDI unit
coupler.
ŒFasten the brake hose between
the paint marks.
ÂPass the brake hose (brake
cable for the TT-R125E)
through the cable guide.
ÍFit the CDI unit band over the
CDI unit bracket till it stops.
ÊFasten the brake cable.
30~35 mm
(1.18~1.38 in)
E
DD
A
C
B-B
D-D
E
B
BC
TT-R125EA
L
1
3
4 2
3
35
3
36
7
3
3
8
9 0 A 3 B C
DEFGHIJKOP
7
4
0
3 3M
N
3Q
3 F
E
DË
◊
„
Ù
AB
AA
Û
ÁAC
N
Ì
Ï ‰ Î
Ç ı Å
Ó
È
Ô

Ò ˜ ˆ Ø ∏
ŒÂÍ ÊÂ

2 - 32
SPECCABLE ROUTING DIAGRAM
ËAfter connecting the main
switch coupler, engine stop
switch coupler, clutch switch
coupler and start switch cou-
pler, put a connector cover on
the couplers and push them in
at the rubber cover end.
◊Pass the wire harness on the
outside of the main switch cou-
pler.
„Do not allow the primary coil
lead to slacken where it is bare
of the protecting tube.ÙFasten the CDI unit lead and
starting circuit cut-off relay lead
with a plastic locking tie at the
tape holding the main switch
lead, engine stop switch lead,
clutch switch lead, and start
switch lead together.
ÁPosition the starter cable, throt-
tle cable, CDI magneto lead,
wire harness and rear shock
absorber assembly sub-tank
hose (TT-R125LWE only) as
shown.ÛFasten the wire harness, throttle
cable, starter cable, CDI mag-
neto lead and rear shock
absorber assembly sub-tank
hose (TT-R125LWE only) at the
protecting tube for the CDI mag-
neto lead.
Fasten the rectifier/regulator
lead as shown.
Do not allow the CDI magneto
lead to slacken.
Position the plastic locking tie
ends as shown.
AA
AB
AC
30~35 mm
(1.18~1.38 in)
E
DD
A
C
B-B
D-D
E
B
BC
TT-R125EA
L
1
3
4 2
3
35
3
36
7
3
3
8
9 0 A 3 B C
DEFGHIJKOP
7
4
0
3 3M
N
3Q
3 F
E
DË
◊
„
Ù
AB
AA
Û
ÁAC
N
Ì
Ï ‰ Î
Ç ı Å
Ó
È
Ô

Ò ˜ ˆ Ø ∏
ŒÂÍ ÊÂ

3 - 3
INSP
ADJ
PRE-OPERATION INSPECTION AND MAINTENANCE
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation or practice, make sure the machine is in good operating condi-
tion.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
FuelCheck that a fresh gasoline is filled in the fuel tank. Check the
fuel line for leakage.P.1-12
Engine oilCheck that the oil level is correct. Check the crankcase for leak-
age.P.3-7 ~ 10
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-4
Throttle grip/housingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P.3-4 ~ 5
BrakesCheck the play of front and rear brake and effect of front and
rear brake.
Check fluid level and leakage. (TT-R125LW/TT-R125LWE only)P.3-15 ~ 20
Drive chainCheck chain slack and alignment. Check that the chain is lubri-
cated properly.P.3-21 ~ 22
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-27 ~ 28
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-28 ~ 32
Front forks and rear shock
absorber assemblyCheck that they operate smoothly and there is no oil leakage. P.3-23 ~ 26
Cables (wires)Check that the clutch and throttle cables move smoothly. Check
that they are not caught when the handlebars are turned or
when the front forks travel up and down.—
Muffler Check that the muffler is tightly mounted and has no cracks. P.4-2
Sprocket Check that the driven sprocket tightening nut is not loose. P.3-20
Lubrication Check for smooth operation. Lubricate if necessary. P.3-33
Bolts and nuts Check the chassis and engine for loose bolts and nuts.—
Lead connectorsCheck that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-5

3 - 24
INSP
ADJ
REAR SHOCK ABSORBER ASSEMBLY
INSPECTION
1. Inspect:
Swingarm smooth action
Abnormal noise/unsmooth action →
Grease the pivoting points or repair the
pivoting points.
Damage/oil leakage → Replace.
REAR SHOCK ABSORBER SPRING
PRELOAD ADJUSTMENT
1. Elevate the rear wheel by placing the
suitable stand under the engine.
2. Remove:
Left side cover
3. Loosen:
Locknut 1
4. Adjust:
Spring preload
By turning the adjuster 2.
NOTE:
Be sure to remove all dirt and mud from
around the locknut and adjuster before
adjustment.
The length of the spring (installed) changes
1.5 mm (0.06 in) per turn of the adjuster.
CAUTION:
Never attempt to turn the adjuster beyond
the maximum or minimum setting.Stiffer →Increase the spring preload.
(Turn the adjuster 2 in.)
Softer →Decrease the spring preload.
(Turn the adjuster 2 out.)
Spring length (installed) a:
Standard length Extent of adjustment
TT-R125/TT-R125E/
TT-R125LW:
165 mm
(6.50 in)
TT-R125LWE:
160.5 mm
(6.32 in)TT-R125/TT-R125E/
TT-R125LW:
155 ~ 175 mm
(6.10 ~ 6.89 in)
TT-R125LWE:
147.5 ~ 167.5 mm
(5.81 ~ 6.59 in)
REAR SHOCK ABSORBER ASSEMBLY INSPECTION/
REAR SHOCK ABSORBER SPRING PRELOAD ADJUSTMENT