engine YAMAHA TTR125 2004 Owners Manual

5 - 65
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.
WARNINGSupport 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

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6 - 1
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
The illustration shows the TT-R125LW
EC600000
ELECTRICAL
EC610000
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
TT-R125/TT-R125LW
EC611000
ELECTRICAL COMPONENTS
1CDI unit
2Engine stop switch
3Ignition coil
4CDI magneto
5Spark plugCOLOR CODE
B ................. Black
Br ................ Brown
G ................. Green
O ................. Orange
R ................. RedW ................ White
B/R.............. Black/Red
B/W ............. Black/White
G/L .............. Green/Blue
G/W ............ Green/WhiteW/L ............. White/Blue
W/R............. White/Red
EC612000
WIRING DIAGRAM

6 - 2
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The illustration shows the TT-R125LWE
12345 7 6890A
EDCB
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
TT-R125E/TT-R125LWE
EC611000
ELECTRICAL COMPONENTS
1CDI unit
2Main switch
3Start switch
4Clutch switch
5Engine stop switch
6Starting circuit cut-off
relay
7Ignition coil
8Battery
9Starter relay
0Fuse
ARectifier/regulator
BNeutral switch
CCDI magneto
DStarter motor
ESpark plugCOLOR 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 - 3
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:
90890-06754Pocket 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.
(TT-R125E/TT-R125LWE
only)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 - 4
–+ELECIGNITION 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
ÅFor USA and CDN
ıExcept 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
(TT-R125E/TT-R125LWE)
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
1Br
2B/W
3B
4Tester selec-
tor position
ON
Ω × 1
OFF
RB/W
BrB
13
24

6 - 5
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ENGINE STOP SWITCH INSPECTION
TT-R125/TT-R125LW
1. Inspect:
Engine stop switch conduct
Not continuous while being pushed →
Replace.
Continuous while being freed → Replace.
TT-R125E/TT-R125LWE
1. Inspect:
Engine stop switch conduct
No continuous while being pushed → Replace.
Continuous while being freed → Replace. Tester (+) lead → Black/White lead 1
Tester (–) lead → Black lead 2
B/W
1B
2Tester selec-
tor position
PUSH IN
Ω × 1
FREE
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.
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

6 - 8
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ELECTRIC STARTING SYSTEM
(TT-R125E/TT-R125LWE)
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 (TT-R125E/TT-R125LWE)

6 - 13
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STARTER MOTOR
7
4
3
52
1
5 8
0
90
95
6
1
New
New
New
Extent of removal:1 Starter motor disassembly
Extent of removal Order Part name Q’ty Remarks
STARTER MOTOR REMOVAL
Preparation for removal Drain the engine oil. Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
1 Starter motor 1
STARTER MOTOR DISASSEM-
BLY
1Starter motor front cover 1
2Washer (starter motor front
cover)1
3Plain washer 1
4Circlip 1
5O-ring
3
1
ELECTRIC STARTING SYSTEM (TT-R125E/TT-R125LWE)

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6 - 18
CHARGING SYSTEM (TT-R125E/TT-R125LWE)
EC680000
CHARGING SYSTEM (TT-R125E/TT-R125LWE)
EC681001
INSPECTION STEPS
If the battery is not charged, use the following inspection steps.
*1 marked: Refer to “FUSE INSPECTION” section in the CHAPTER 3.
*2 marked: Refer to “BATTERY INSPECTION AND CHARGING” section in the CHAPTER 3.
NOTE:
Remove the following parts before inspection.
1) Seat
2) Rear fender
3) Fuel tank
Use the following special tool in this inspection.
Pocket tester:
YU-3112-C/90890-03112Inductive tachometer:
YU-8036-B
Engine tachometer:
90890-03113
*1 Check fuse.Replace fuse and
check wire harness.
*2 Check battery. Recharge or replace.
Check each coupler and
wire connection.Repair or replace.
Check charging voltage.Charging system is
good.
Check CDI magneto. Charging coil Replace.
Replace rectifier/regulator.
OK
OK
OK
No good
OK
No good
No good
No good
No good
OK

6 - 19
–+ELECCHARGING SYSTEM (TT-R125E/TT-R125LWE)
EC624000
COUPLERS AND LEADS CONNECTION
INSPECTION
1. Check:
Couplers and leads connection
Rust/dust/looseness/short-circuit →
Repair or replace.
CHARGING VOLTAGE INSPECTION
1. Start the engine.
2. Inspect:
Charging voltage
Out of specification → If no failure is
found in checking the source coil resis-
tance, replace the rectifier/regulator.
Tester (+) lead → Red lead 1
Tester (–) lead → Black lead 2
Charging
voltageTester selector
position
14.0 ~ 15.0 V at
5,000 r/minDCV-20
W
B
RY
2
1
3. Inspect:
Charging coil resistance
Out of specification → Replace.
Tester (+) lead → White lead 1
Tester (–) lead → Black lead 2
Charging coil
resistanceTester selector
position
0.64 ~ 0.96 Ω at
20 ˚C (68 ˚F)Ω × 1
WSb
YB
1
2