Yamaha YJ125S Service Manual page 281

EAS00823
4. Thermo switch
8 Remove the thermo switch from the
thermo switch plate wire harness.
8 Connect the pocket tester to the (Ω × 1)
to the thermo switch 1 as shown.
NOTE:
Make sure that the thermo switch terminals
do not get wet.
8 Immerse the thermo switch in a container
filled with coolant 2.
8 Place a thermometer3 in the coolant.
8 Slowly heat the coolant, then let it cool
down to the specified temperature.
8 Check the thermo switch for continuity
at the temperature indicated below.
Test step C o o l a n t
temperature
1 0 ~11 ± 3 °C
2 More than16 ± 3 °C
3* 16 ± 3 ~ 11±3 °C
4* Less than11 ± 3 °C
Steps 1 & 2: Heating phase
Steps 3 & 4: Cooling phase
3
1
2
w
8 8 8 8 8 Handle the thermo switch with special
care.
8 8 8 8 8 Never subject the thermo switch to
strong shocks. If the thermo switch is
dropped, replace it.
CRABURETOR HEATING SYSTEM
Continuity
YES
NO
NO
YES
7-43
A The coolant temperature sensor circuit is
closed.
B The coolant temperature sensor circuit is
open.
ON
11 ± 3˚C
B
8 Does the thermo switch operate prop-
erly?
YES
EAS00824
5. Carburetor heater
8Remove the carburetor heating element
from the carburetor.
8Connect the pocket tester to the carbu-
retor heating element as shown.
Positive tester probe
Negative tester probe
body 2 2 2 2 2
8Measure the carburetor heater resis-
tance.
1
2
Carburetor heating element resis-
tance
30 Ω Ω Ω Ω Ω at 20°C
8Is the carburetor heating element OK?
YES
-
ELEC
OFF
16 ± 3˚C
A
NO
Replace the thermo
switch.
heating element 1 1 1 1 1
heating element
NO
Replace the carburetor
heating element.
+