engine YAMAHA TTR125 2003 Owners Manual

5 - 42
CHASHANDLEBAR
TT-R125LWE
Extent of removal:1 Handlebar removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalHANDLEBAR REMOVAL
Number plate
1 Clutch cable 1
2 Clutch lever 1
3 Engine stop switch 1
4 Brake master cylinder 1 Refer to “REMOVAL POINTS”.
5 Start switch 1
6 Grip cap (lower) 1
7 Grip cap (upper) 1
8 Throttle cable 1
9 Throttle grip assembly 1
10 Handlebar grip (left) 1 Refer to “REMOVAL POINTS”.
11 Main switch 1
12 Upper handlebar holder 2
13 Handlebar 1
1

5 - 47
CHAS
6. Install:
TT-R125E
Start switch 1
Bolts (start switch) 2
Front brake cable 3
Clamp
NOTE:
Apply the lithium soap base grease on the
front brake cable end.
TT-R125LWE
Start switch 1
Brake master cylinder 2
Brake master cylinder bracket 3
Bolt (brake master cylinder bracket) 4
NOTE:
Install the bracket so that the arrow mark a
face upward.
First tighten the bolts on the upper side of the
brake master cylinder bracket, and then
tighten the bolts on the lower side.
7. Install:
Engine stop switch 1
Clutch lever holder 2
Screws (clutch lever holder) 3
NOTE:
The engine stop switch and clutch lever
holder should be installed according to the
dimensions shown.
Pass the engine stop switch lead in the mid-
dle of the clutch lever holder.
8. Install:
Clutch cable 1
Clamp
NOTE:
Apply the lithium soap base grease on the
clutch cable end.
9. Adjust:
Brake lever free play
Refer to “FRONT BRAKE ADJUST-
MENT” section in the CHAPTER 3.
Clutch lever free play
Refer to “CLUTCH ADJUSTMENT”
section in the CHAPTER 3.
3
1
2
LS
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)
U P3 2
4 4
a1
T R..9 Nm (0.9 m · kg, 6.5 ft · lb)
12 3
3T R..4 Nm (0.4 m · kg, 2.9 ft · lb)
HANDLEBAR

5 - 48
CHASSTEERING
EC560000
STEERING
Extent of removal:1 Lower bracket removal2 Bearing removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalSTEERING REMOVAL
Hold the machine by placing the
suitable stand under the engine.
WARNING
Support the machine securely so there is nodanger of it falling over.
Front forks Refer to “FRONT FORK” section.
Handlebar Refer to “HANDLEBAR” section.
Front fender
1 Steering stem nut 1
2 Upper bracket 1
3 Special washer 1
4 Upper ring nut 1
Use special tool.
Refer to “REMOVAL POINTS”. 5 Rubber washer 1
6 Lower ring nut 1
7 Lower bracket 1
8Bearing cover
1
21

5 - 54
CHASSWINGARM
EC570000
SWINGARM
Extent of removal:1 Swingarm removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalSWINGARM REMOVAL
Hold the machine by placing the
suitable stand under the engine.
WARNING
Support the machine securely so there is nodanger of it falling over.
Rear wheel Refer to “REAR WHEEL AND REAR
BRAKE” section.
1 Drive chain tensioner (upper) 1
2 Drive chain tensioner (lower) 1
3 Bolt (connecting arm-frame) 1
4 Bolt (rear shock absorber-relay arm) 1Hold the swingarm.
5 Pivot shaft 1
6 Swingarm 1
1

5 - 61
CHASREAR SHOCK ABSORBER ASSEMBLY
EC580000
REAR SHOCK ABSORBER ASSEMBLY
Extent of removal:1 Rear shock absorber assembly removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalREAR SHOCK ABSORBER
ASSEMBLY REMOVAL
Hold the machine by placing the
suitable stand under the engine.
WARNING
Support the machine securely so there is nodanger of it falling over.
Seat and side covers Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section in the CHAPTER 4.
1 Bolt (rear shock absorber assem-
bly-relay arm)1 Hold the swingarm.
2 Bolt (rear shock absorber assem-
bly-frame)1
3 Bushing 1 Refer to “REMOVAL POINTS”.
4 Rear shock absorber assembly 1
1

6 - 1
–+ELEC

* The illustration shows the TT-R125LWE
12345 7 6890A
EDCB

ELECTRICAL COMPONENTS AND WIRING DIAGRAM
EC600000
ELECTRICAL
EC610000
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
EC611000
ELECTRICAL COMPONENTS
1
CDI unit
2
Main switch
3
Start switch
4
Clutch switch
5
Engine stop switch
6
Starting circuit cut-off
relay
7
Ignition coil
8
Battery
9
Starter relay
0
Fuse
A
Rectifier/regulator
B
Neutral switch
C
CDI magneto
D
Starter motor
E
Spark plug
COLOR CODE
B ...................... Black
Br ..................... Brown
G...................... Green
O...................... Orange
R ...................... Red
Sb .................... Sky blueW ..................... White
Y ...................... Yellow
B/W.................. Black/White
L/Y ................... Blue/Yellow
R/W ................. Red/White
EC612000
WIRING DIAGRAM
B
R/W
WB
RYW
BR Y
10A
R
BR/W
ON
OFFR
BrRB/WBB/WBr B
ON OFF
R/WBr BB
R/WSbR/W
BB BL/Y
OFF RUN
BBBB/W
W
YWSbBSbY B
G
WBrRG
WBrRB
B/WR
W Br
GO
R
SbR/WR/WR/WR/W
R/W
B
R
B/WBrBr
B
L/Y
BSb
YW
RWBrG
RWBrG
B/W
B/W
BOO
B
B
1
2
3
45 67
8
90 A
BC
DE

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6 - 2
IGNITION SYSTEM
EC620000
IGNITION SYSTEM
INSPECTION STEPS
Use the following steps for checking the possibility of the malfunctioning engine being attributable to
ignition system failure and for checking the spark plug which will not spark.
*marked: Only when the ignition checker is used.
NOTE:


Remove the following parts before inspection.
1) Seat
2) Fuel tank

Use the following special tools in this inspection.
Dynamic spark tester:
YM-34487
Ignition checker:
90890-06754
Pocket tester:
YU-3112-C/90890-03112
Spark gap test*Clean or replace
spark plug.
Check entire ignition
system for connection.Repair or replace.
Check main switch. Replace.
Check engine stop switch. Replace.
Check ignition coil. Primary coil Replace.
Secondary coil Replace.
Check CDI magneto. Pickup coil Replace.
Source coil Replace.
Replace CDI unit.
No Spark
OK
OK
OK
OK
Spark
No good
No good
No good
No good
No good
No good
OK
No good

6 - 3
–+ELEC

IGNITION SYSTEM
EC622001
SPARK GAP TEST
1. Disconnect the spark plug cap from spark
plug.
2. Connect the dynamic spark tester
1
(ignition checker
2
) as shown.

Spark plug cap
3


Spark plug
4

Å
For USA and CDN
ı
Except for USA and CDN
3. Kick the kick starter.
4. Check the ignition spark gap.
5. Start engine, and increase spark gap until
misfire occurs. (for USA and CDN only)
Minimum spark gap:
6.0 mm (0.24 in)
Å
ı

EC624000
COUPLERS AND LEADS CONNECTION
INSPECTION
1. Check:

Couplers and leads connection
Rust/dust/looseness/short-circuit
→

Repair or replace.
MAIN SWITCH INSPECTION
1. Inspect:

Main switch continuity
Check for continuity as follows:
Incorrect continuity
→
Replace.
Tester (+)
→
Red lead
1

Tester (–)
→
Brown lead
2
Continuous
Tester (+)
→

Black/White lead
3
Tester (–)
→
Black lead
4
Continuous
R
1
Br
2
B/W
3
B
4Tester selec-
tor position
ON
Ω × 1
OFF
RB/W
BrB
13
24

6 - 4
–+ELECIGNITION SYSTEM
ENGINE STOP SWITCH INSPECTION
1. Inspect:
Engine stop switch continuity
No continuous while being pushed → Replace.
Continuous while being free → Replace. Tester (+) lead → Black lead 1
Tester (–) lead → Black lead 2
B
1B
2Tester selec-
tor position
PUSH IN
Ω × 1
FREE
BB
1
2
EC626002
IGNITION COIL INSPECTION
1. Inspect:
Primary coil resistance
Out of specification → Replace.
2. Inspect:
Secondary coil resistance
Out of specification → Replace.
NOTE:
When inspecting the secondary coil resis-
tance, remove the spark plug cap.Tester (+) lead → Orange lead 1
Tester (–) lead → Black lead 2
Primary coil
resistanceTester selector
position
0.18 ~ 0.28 Ω at
20 ˚C (68 ˚F)Ω × 1
Tester (+) lead → Spark plug lead 1
Tester (–) lead → Orange lead 2
Secondary coil
resistanceTester selector
position
6.3 ~ 9.5 kΩ at
20 ˚C (68 ˚F)kΩ × 1

6 - 6
–+ELEC
ELECTRIC STARTING SYSTEM
STARTING CIRCUIT CUT-OFF SYSTEM
OPERATION
If the main switch is set to “ON”, the starter
motor can only operate if at least one of the
following conditions is met:
The transmission is in neutral (the neutral
switch is closed).
The clutch lever is pulled to the handlebar
(the clutch switch is closed).
The starting circuit cut-off relay prevents the
starter motor from operating when neither of
these conditions has been met. In this
instance, the starting circuit cut-off relay is
open so current cannot reach the starter
motor. When at least one of the above condi-
tions has been met the starting circuit cut-off
relay is closed and the engine can be started
by pressing the start switch.
WHEN THE TRANSMISSION IS
IN NEUTRAL
WHEN THE CLUTCH LEVER IS
PULLED TO THE HANDLEBAR
1Battery
2Main fuse
3Main switch
4Start switch
5Starting circuit cut-off relay
6Neutral switch
7Clutch switch
8Starter relay
9Starter motor
12
M
3
8
54
6 9
7
ELECTRIC STARTING SYSTEM