Yamaha YZ 2018 Series, Owner'S Service Manual, Page: 294 / 402

THROTTLE BODY
7-9
EASB29B318
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 8-23.
Deposits

Replace.
Damage

Replace.
2. Check:
• Injector resistance
Refer to “CHECKING THE FUEL INJEC-
TOR” on page 8-72.
EASB29B319
CHECKING THE THROTTLE BODY
1. Check:
• Throttle body
Cracks/damage

Replace.
2. Check:
• Fuel passages
Obstructions

Clean.
ECA
NOTICE
• 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”. A loss of perfor-
mance 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.
3. Check:
• Starter knob/idle screw passage “c”
Obstruction

Blow out with compressed
air.
EASB29B320
CHECKING THE THROTTLE BODY JOINT
1. Check:
• Throttle body joint “1”
Crack/damage

Replace.
1
2
3
b
a
c
1