Yamaha 2011 WR250FA Owner's Service Manual page 313

2. Set the main switch to "ON".
3. Measure:
• Speed sensor output voltage
Output voltage not correct → Replace the
speed sensor.
Measurement steps:
a. Elevate the front wheel and slowly rotate it.
b. Measure the voltage (DCV) of white lead
and black lead. With each full rotation of the
front wheel, the voltage reading should cycle
from 0.6 V to 4.8 V to 0.6 V to 4.8 V.
SIGNALING SYSTEM
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