Yamaha YBR 125 Service Manual page 195

Starting system
3.Measure
The depth of mica sheet slot a
Out of normal range→grind it with hand saw to make
it fits to normal value.
Note:
The insulated mica sheet of commutator must has
slot ,which can sure the normal work of the com-
mitator.
4. Check
Electric coil(insulation,conduction)
If there is default→replace the starting motor
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Inspection procedure
Connect min.multitester for the test of conduction and
insulatiom
Measure the resistance value of the electric button.
Resistance value of electric button coil
0.017~0.021Ω,at 20°C 68 F
more than 1MΩ at 20 °C 68 F
If the resistance value is abnormal,replace the starting mot
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5. Measure
Electric brush length a
Out of normal value→Replace the electric brush as a se
Lengh limit value of the electric brush
Note:
When replacing the electric brush, pay more atte-
ntion to one side which is welding.
7-19
ELEC
Depth of the mica slot
1.5mm
********
Conduction test
Insulation test
********
t
3.5mm(0.14in)