Yamaha XV19SX(C), Service Manual, Page: 385 / 494

THROTTLE BODIES
6-16
f. Start the engine.
g. Measure the fuel pressure.
h. Use the vacuum/pressure pump gauge set to
adjust the fuel pressure in relation to the vac-
uum pressure as described below.
NOTE:
The vacuum pressure should not exceed 100
kPa (760 mmHg).
Faulty
→
Replace the pressure regulator.
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EAS27030
ADJUSTING THE THROTTLE POSITION
SENSOR
1. Check:
• Throttle position sensor
Refer to “CHECKING THE THROTTLE PO-
SITION SENSOR” on page 7-89.
2. Adjust:
• Throttle position sensor angle
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a. Connect the throttle position sensor coupler
to the throttle position sensor.
b. Connect the digital circuit tester to the throttle
position sensor.
c. Turn the main switch to “ON”.
d. Measure the throttle position sensor output
voltage.
e. Adjust the throttle position sensor angle so
that the output voltage is within the specified
range.
f. After adjusting the throttle position sensor an-
gle, tighten the throttle position sensor
screws “3”.
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ET1D71008
INSTALLING THE FUEL PIPE
1. Install:
• Fuel pipe “1”
Vacuum/pressure pump gauge
set
90890-06756
Mityvac brake bleeding tool
YS-42423
Pressure gauge
90890-03153
YU-03153
Fuel pressure adapter
90890-03176
YM-03176
Fuel pressure
392 kPa (3.92 kg/cm², 55.7 psi)
• Increase the vacuum pressure
→
Fuel pressure is decreased
• Decrease the vacuum pressure
→
Fuel pressure is increased
1
2
4
2
5
3
1
• Positive tester probe
yellow terminal “1”
• Negative tester probe
black terminal “2”
Digital circuit tester
90890-03174
Model 88 Multimeter with ta-
chometer
YU-A1927
Output voltage (at idle)
0.63–0.73 V
3
3
1
2