2001 YAMAHA YZ125LC ignition

3-40
IGNITION TIMING CHECK
INSP
ADJ
7. Adjust:
9Ignition timing
Adjustment steps:
9Loosen the screws (stator) 1.
9Align the punch mark on the rotor with
punch mark on the stator 2by moving the
stator.
9Tighten the screws (stator).
Screw (stator):
8 Nm (0.8 m•kg, 5.8 ft•lb)
5MV-9-30-3B 6/19/00 1:50 PM Page 44

4-55
ENGCDI MAGNETO
2. Install:
9Woodruff key 1
9Rotor 2
NOTE:
9Clean the tapered portions of the crankshaft
and rotor.
9When installing the woodruff key, make sure
that its flat surface ais in parallel with the
crankshaft center line b.
9When installing the rotor, align the keyway c
of the rotor with the woodruff key.
3. Install:
9Plain washer 1
9Nut (rotor) 2
Use the rotor holding tool 3.
4. Adjust:
9Ignition timing
Refer to “IGNITION TIMING CHECK” sec-
tion in the CHAPTER 3.
5. Tighten:
9Screw (stator) 1
6. Check:
9Ignition timing
Re-check the ignition timing.
33 Nm (3.3 m•kg, 24 ft•lb)
Rotor holding tool:
YU-1235/90890-01235
8 Nm (0.8 m•kg, 5.8 ft•lb)
Ignition timing (B.T.D.C.):
0.52 mm (0.020 in)
5MV-9-30-4C 6/19/00 1:42 PM Page 36

6-1
ELECELECTRICAL COMPONENTS AND WIRING DIAGRAM
EC600000
ELECTRICAL
EC610000
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
EC611000
ELECTRICAL COMPONENTS
1“ENGINE STOP” button
2Ignition coil
3CDI unit
4CDI magneto
5Spark plug
EC612000
WIRING DIAGRAM
COLOR CODE
B...................Black
O ..................Orange
B/R ...............Brack/Red
B/W ..............Black/White
G/L ..............Green/Blue
G/W ..............Green/White
W/L...............White/Blue
W/R ..............White/Red
6
5MV-9-30-6 6/19/00 1:25 PM Page 2

6-2
ELECIGNITION SYSTEM
EC620000
IGNITION SYSTEM
EC621002
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.
*Clean or replace
spark plug.
Primary coil
Secondary coil
Repair or replace.
Spark
Check entire ignition
system for connection.
Spark gap test
No good
No good
No good
No good
No good
No good No Spark
Check “ENGINE STOP”
button.
Pick-up coil
Source coil
Check ignition coil.
Check CDI magneto.
Replace CDI unit.
Replace.
Replace.
Replace.
Replace.
Replace.
*marked: Only when the ignition checker is used.
NOTE:
9Remove the following parts before inspection.
1) Seat
2) Fuel tank
9Use the following special tools in this inspection.
Dynamic spark tester:
YM-34487
Ignition checker:
90890-06754Pocket tester:
YU-3112-C/90890-03112
OK
OK
OK
OK
5MV-9-30-6 6/19/00 1:25 PM Page 4

6-3
ELECIGNITION SYSTEM
EC622001
SPARK GAP TEST
1. Disconnect the spark plug cap from spark
plug.
2. Connect the dynamic spark tester 1(igni-
tion checker 2) as shown.
9Spark plug cap 3
9Spark plug 4
AFor USA and CDN
BExcept 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)
EC624000
COUPLERS AND LEADS CONNECTION
INSPECTION
1. Check:
9Couplers and leads connection
Rust/ Dust/ Looseness/Short-circuit Õ
Repair or replace.
EC625002
“ENGINE STOP” BUTTON INSPECTION
1. Inspect:
9“ENGINE STOP” button conduct
Not continuous while being pushed ÕReplace.
Continuous while being freed ÕReplace.
Minimum spark gap:
6.0 mm (0.24 in)
Tester (+) leadÕBlack/White lead 1
Tester (–) lead
ÕBlack lead 2
B/W B
12
PUSH IN
FREE
Tester selector
position
½´ 1
Œ
º
5MV-9-30-6 6/19/00 1:25 PM Page 8

6-4
ELECIGNITION SYSTEM
EC626002
IGNITION COIL INSPECTION
1. Inspect:
9Primary coil resistance
Out of specification ÕReplace.
2. Inspect:
9Secondary coil resistance
Out of specification ÕReplace.
NOTE:
When inspecting the secondary coil resistance,
remove the spark plug cap.
Tester (+) leadÕOrange lead 1
Tester (–) lead
ÕBlack lead 2
Tester (+) leadÕSpark plug lead 1
Tester (–) lead
ÕOrange lead 2
Primary coil Tester selector
resistance position
0.14~0.20½at
½´ 1
20°C (68°F)
Secondary coil Tester selector
resistance position
6.7~10.1k½at
k½´ 1
20°C (68°F)
5MV-9-30-6 6/19/00 1:25 PM Page 10

6-5
ELECIGNITION SYSTEM
EC627011
CDI MAGNETO INSPECTION
1. Inspect:
9Pick-up coil resistance
Out of specification ÕReplace.
2. Inspect:
9Source coil 1 resistance
Out of specification ÕReplace.
3. Inspect:
9Source coil 2 resistance
Out of specification ÕReplace.
EC628000
CDI UNIT INSPECTION
Check all electrical components. If no fault is
found, replace the CDI unit. Then check the
electrical components again.
Tester (+) leadÕWhite/Red lead 1
Tester (–) lead
ÕWhite/Blue lead 2
Pick–up coil Tester selector
resistance position
248~372½at
½´ 100
20°C (68°F)
Tester (+) leadÕBlack/Red lead 1
Tester (–) lead
ÕGreen/Whitelead 2
Source coil 1 Tester selector
resistance position
720~1,080½at
½´ 100
20°C (68°F)
Tester (+) leadÕGreen/Blue lead 1
Tester (–) lead
ÕBlack lead 2
Source coil 2 Tester selector
resistance position
44~66½at
½´ 10
20°C (68°F)
5MV-9-30-6 6/19/00 1:25 PM Page 12