engine YAMAHA TTR125 2002 Owners Manual
Page 496 of 509
 
6 - 1
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* The illustration shows the TT-R125LW 
ELECTRICAL COMPONENTS AND WIRING DIAGRAM 
EC600000 
ELECTRICAL 
EC610000 
ELECTRICAL COMPONENTS AND WIRING DIAGRAM 
EC611000 
ELECTRICAL COMPONENTS 
1  
CDI unit  
2  
Engine stop switch  
3 
Ignition coil  
4 
CDI magneto 
5 
Spark plug 
COLOR CODE 
B...................... Black
Br .................... Brown
G ..................... Green
O ..................... Orange
R ..................... Red
W..................... WhiteB/R .................. Black/Red
B/W ................. Black/White
G/L .................. Green/Blue
G/W ................. Green/White
W/L .................. White/Blue
W/R ................. White/Red 
EC612000 
WIRING DIAGRAM 
6 
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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:
 
l 
Remove the following parts before inspection.
1) Seat
2) Fuel tank 
l 
Use the following special tools in this inspection. 
Spark gap test*Clean or replace 
spark plug.
Check entire ignition
system for connection.Repair or replace.
Check engine stop switch. Replace.
Check ignition coil. Primary coil Replace.
Secondary coil Replace.
Check CDI magneto. Pickup coil Replace.
Charging coil Replace.
Replace CDI unit. 
Dynamic spark tester:
YM-34487
Ignition checker:
90890-06754 
Pocket tester:
YU-3112-C/90890-03112 
No Spark
OK
OK
OK
OK
Spark
No good
No good
No good
No good
No good
No good 
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IGNITION SYSTEM 
SPARK GAP TEST  
1. Disconnect the spark plug cap from spark
plug.
2. Connect the dynamic spark tester   
1  
(ignition checker   
2  
) as shown. 
l 
Spark plug cap   
3  
  
l 
Spark plug   
4  
  
  
For USA and CDN  
õ  
Except for USA and CDN 
3. Kick the kickstarter crank.
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)
õ
 
EC624000 
COUPLERS AND LEADS CONNECTION 
INSPECTION  
1. Check: 
l 
Couplers and leads connection
Rust/dust/looseness/short-circuit   
®  
 
Repair or replace.  
ENGINE STOP SWITCH INSPECTION  
1. Inspect: 
l 
Engine stop switch conduct.
Not continuous while being pushed   
®  
 
Replace.
Continuous while being freed  
®  
 Replace.  
Tester (+) lead   
®  
 Black/White lead   
1  
 
Tester (–) lead  
®  
 Black lead   
2  
  
B/W   
1  
B  
2  
Tester selec-
tor position
PUSH IN 
W  
   
´  
 1
FREE