Checking The Injector; Checking The Throttle Body; Checking The Throttle Body Joint - Yamaha YZ450FX 2019 Owner's Service Manual

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CHECKING THE INJECTOR

1. Check:
• Injectors
Obstruction  Replace, and check the fuel
pump and the fuel injection system.
Refer to "FUEL INJECTION SYSTEM" on
page 8-21.
Deposits  Replace.
Damage  Replace.
2. Check:
• Injector resistance
Refer to "CHECKING THE FUEL INJEC-
TOR" on page 8-68.
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CHECKING THE THROTTLE BODY

1. Check:
• Throttle body
Cracks/damage  Replace.
2. Check:
• Fuel passages
Obstructions  Clean.
ECA26070
NOTICE
• Before removing the throttle body, clean
the area around the throttle body to prevent
dirt and other foreign material from falling
into the engine.
• If the throttle body is subject to strong
shocks or dropped during cleaning, re-
place it.
• Do not use any caustic carburetor cleaning
solution.
• Do not directly push the throttle valves to
open them.
• Do not loosen the throttle valve stopper
screw "1", throttle valve pulley nut "2",
throttle valve screw "3" or starter knob nut
"4". A loss of performance may occur.
• Do not use compressed air to clean the
throttle body. Foreign materials may ad-
here to the intake air pressure sensor pas-
sage "a" and fuel injector "b" in the throttle
body.
2
b
4
3. Check:
• Idle screw "1" passage "c"
Obstruction  Blow out with compressed air.
1
c
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CHECKING THE THROTTLE BODY JOINT

1. Check:
• Throttle body joint "1"
Crack/damage  Replace.
7-8
THROTTLE BODY
1
3
a