Yamaha YZ450FA 2011 Owner's Service Manual page 261

CHECKING THE INJECTOR
Replace the fuel injector with a new one if
you have dropped or impacted it.
1. Check:
• Injectors
Damage → Replace.
CHECKING THE THROTTLE BODY
• Before removing the throttle body, clean
the area around the throttle body to pre-
vent 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 clean-
ing 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", or
throttle valve screw "3". Otherwise, a loss
of performance may occur.
• Do not use compressed air to clean the
throttle body. Otherwise, foreign material
may adhere to the intake air pressure sen-
sor passage "a" and fuel injector "b" in the
throttle body.
1. Check:
• Throttle body
Cracks/damage → Replace the throttle body
as a set.
2. Check:
• Starter knob/ idle screw delivery passages
"a"
Obstructions → Blow out with compressed
air.
ASSEMBLING THE THROTTLE BODY
1. Install:
• O-ring "1"
• Injector "2"
• Bolt "3"
Bolt (injector)
3 Nm (0.3 m•kg, 2.2 ft•lb)
Always use a new O-ring.
6-8
THROTTLE BODY