Throttle Bodies; Checking The Injectors; Checking The Throttle Bodies; Checking The Pressure Regulator - Yamaha WR250R Service Manual

EAS26980

CHECKING THE INJECTORS

EWA32D1009
WARNING
Replace the fuel injector with a new one if
you have dropped or impacted it.
1. Check:
Injectors
G
Damage → Replace.
EAS26990

CHECKING THE THROTTLE BODIES

1. Check:

Throttle bodies

G
Cracks/damage → Replace the throttle bod-
ies as a set.
2. Check:
Fuel passages
G
Obstructions → Clean.
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
a. Wash the throttle bodies in a petroleum-
based solvent.
Do not use any caustic carburetor cleaning
solution.
b. Blow out all of the passages with com-
pressed air.
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EAS27000

CHECKING THE PRESSURE REGULATOR

EWA32D1010
WARNING
Replace the pressure regulator with a new
one if you have dropped or impacted it.
1. Check:
Pressure regulator
G
Damage → Replace.
EAS27010
CHECKING THE PRESSURE REGULATOR
OPERATION
1. Check:
Pressure regulator operation
G
THROTTLE BODIES
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
a. Remove the fuel tank.
Refer to "FUEL TANK" on page 7-1.
b. Connect the pressure gauge "1" and adapter
"2" to the fuel injection pipe.
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
c. Install the fuel tank.
Refer to "FUEL TANK" on page 7-1.
d. Start the engine.
e. Measure the fuel pressure.
Fuel pressure
250 kPa (35.6 psi) (2.50 kg/cm
f. 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 (14.2 psi) (1.00 kg/cm
Increase the vacuum pressure →
Fuel pressure is decreased
Decrease the vacuum pressure →
Fuel pressure is increased
Faulty → Replace the pressure regulator.
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7-6
2
)
2
).