Yamaha YZ 2019 Series, Owner'S Service Manual

Page: 294 / 398

THROTTLE BODY
7-9
EAM30271
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 8-19.
Deposits

Replace.
Damage

Replace.
2. Check:
•
Injector resistance
Refer to “CHECKING THE FUEL INJEC-
TOR” on page 8-67.
EAM30272
CHECKING THE THROTTLE BODY
1. Check:
• Throttle body
Cracks/damage

Replace.
2. Check:
•
Fuel passages
Obstructions

Clean.
NOTICE
ECA24760
• 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”, 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.
EAM30345
CHECKING THE THROTTLE BODY JOINT
1. Check:
• Throttle body joint “1”
Crack/damage

Replace.
1
2
3
b
a
c