2007 YAMAHA TTR125 check engine

4 - 63
ENG
CDI MAGNETO AND STARTER CLUTCH
(TT-R125E/TT-R125LWE)
3. Check:
Starter clutch operation
Install the starter clutch drive gear 1 onto
the starter clutch 2 and hold the starter
clutch.
When turning the starter clutch drive gear
counterclockwise ı, the starter clutch and
the starter clutch drive gear should
engage. If the starter clutch drive gear and
starter clutch do not engage, the starter
clutch is faulty and must be replaced.
When turning the starter clutch drive gear
clockwise Å, it should turn freely.
If the starter clutch drive gear does not
turn freely, the starter clutch is faulty and
must be replaced.
Å
ı
1
2
EC4L5000
ASSEMBLY AND INSTALLATION
CDI magneto
1. Install:
Stator 1
Bolt (stator)
Lead guide
Screw (lead guide) 2
Pickup coil 3
Bolt (pickup coil)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)LT
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)LT
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)LT
2. Install:
Stater idle gear 1
Plate 2
Bolt 3
Washer 4
NOTE:
Apply the engine oil on the starter idle gear
inner circumference.
4
1
2
3
ET R..7 Nm (0.7 m · kg, 5.1 ft · lb)

4 - 72
ENGCRANKCASE, CRANKSHAFT AND BALANCER
REMOVAL POINTS
Crankcase
1. Remove:
Bolt (crankcase)
Lead guide 1
Clutch cable holder 2
NOTE:
Loosen each bolt 1/4 of a turn at a time and
after all the bolts are loosened, remove them.
2. Remove:
Right crankcase 1
Use the crankcase separating tool 2.
NOTE:
Fully tighten the tool holding bolts, but make
sure the tool body is parallel with the case. If
necessary, one screw may be backed out
slightly to level tool body.
As pressure is applied, alternately tap on the
front engine mounting boss and transmission
shafts.
CAUTION:
Use soft hammer to tap on the case half.
Tap only on reinforced portions of case. Do
not tap on gasket mating surface. Work
slowly and carefully. Make sure the case
halves separate evenly. If one end “hangs
up”, take pressure off the push screw, re-
align, and start over. If the cases do not
separate, check for a remaining case screw
or fitting. Do not force.
Crankcase separating tool:
YU-1135-A/90890-01135

4 - 83
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
Shift cam and shift fork
1. Install:
Shift fork 1 (L) 1
Shift fork 2 (C) 2
Shift fork 3 (R) 3
NOTE:
Mesh the shift fork #1 (L) with the 2nd wheel
gear and #3 (R) with the 4th wheel gear on
the drive axle.
Mesh the shift fork #2 (C) with the 3rd pinion
gear on the main axle.
2. Install:
Shift cam 1
NOTE:
Apply the engine oil on the shift cam.
3. Install:
Shift fork guide bar 1 (short) 1
Shift fork guide bar 2 (long) 2
NOTE:
Apply the engine oil on the guide bars.
Be sure the long bar is inserted into the shift
forks #1 and #3 and the short one into #2.
4. Check:
Shifter operation
Transmission operation
Unsmooth operation → Repair.

–+ELEC
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

–+ELEC
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