Checking The Speed Sensor; Checking The Throttle Position Sensor - Yamaha SR400 2014 Service Manual

2. Remove:
• Fuel sender coupler
(from the wire harness)
3. Check:
• Fuel sender resistance
Sender unit resistance (thermis-
tor)
1350–1900 @25 C (1350–1900
@77 F)
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a. Connect the pocket tester (  1k) to the fuel
sender coupler.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe
green "1"
• Negative tester probe
black "2"
b. Measure the fuel sender resistance.
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EAS28241

CHECKING THE SPEED SENSOR

1. Remove:
• Headlight unit assembly
Refer to "STEERING HEAD" on page 4-44.
2. Check:
• Speed sensor output voltage
Out of specification  Replace the speedom-
eter.
Speed sensor output voltage cy-
cle
0 V 5 V 0 V 5 V
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a. Connect the speed sensor coupler to the wire
1 2
7-70
ELECTRICAL COMPONENTS
harness.
b. Connect the pocket tester (DC 20 V) to the
speed sensor coupler as shown.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe
white "1"
• Negative tester probe
black "2"
c. Turn the main switch to "ON".
d. Elevate the front wheel and slowly rotate it.
e. Measure the voltage. With each full rotation
of the front wheel, the voltage reading should
cycle from 0 V  5 V  0 V  5 V.
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3. Install:
• Headlight unit assembly
Refer to "STEERING HEAD" on page 4-44.
EAS28300
CHECKING THE THROTTLE POSITION
SENSOR
1. Remove:
• Throttle position sensor
(from the throttle body)
2. Check:
• Throttle position sensor maximum resistance
Out of specification  Replace the throttle
position sensor.
Throttle position sensor
Resistance
1.75–3.25 k (L-B/L)
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a. Connect the pocket tester (  1k) to the
throttle position sensor as shown.
1
2