Yamaha 2011 FZ8NA(C), Service Manual, Page: 119 / 478

PERIODIC MAINTENANCE
3-10
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a. Start the engine, warm it up for several
minutes, and then let it run at the specified
engine idling speed.
b. Check the vacuum pressure.
If out of specification
→
Adjust the throttle
bodies synchronization.
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Adjusting the throttle bodies synchroniza-
tion
1. Adjust:
• Throttle bodies synchronization
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a. With throttle body #3 “1” as standard,
adjust throttle bodies #1 “3”, #2 “2”, and #4
“4” using the air screws “5”.
ECA14900
Do not use the throttle valve adjusting
screws to adjust the throttle bodies syn-
chronization.
TIP
• After each step, rev the engine two or three
times, each time for less than a second, and
check the synchronization again.
• If a bypass air screw was removed, turn in
the screw fully and be sure to synchronize
the throttle bodies.
• If the throttle bodies synchronization cannot
adjusted by the bypass air screw, clean or
replace the throttle bodies.
• The difference in vacuum pressure between
the throttle bodies should not exceed 1.33
kPa (10 mmHg).
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2. Measure:
• Engine idling speed
Out of specification
→
Adjust.
Make sure that the vacuum pressure is
within specification.
3. Stop the engine and remove the measuring
equipment.
4. Install:
• Synchronizing hoses
5. Adjust:
• Throttle cable free play
Refer to “ADJUSTING THE THROTTLE
CABLE FREE PLAY” on page 3-29.
6. Install:
• Fuel tank
Refer to “FUEL TANK” on page 7-1.
• Rider seat
Refer to “GENERAL CHASSIS” on page
4-1.
EAS21010
CHECKING THE THROTTLE BODY JOINTS
1. Remove:
• Throttle bodies
Refer to “THROTTLE BODIES” on page
7-6.
2. Check:
• Throttle body joints “1”
Cracks/damage
→
Replace.
Engine idling speed
1150–1250 r/min
The difference in vacuum pres-
sure between the throttle bod-
ies should not exceed 1.33 kPa
(10 mmHg).
Throttle cable free play
3.0–5.0 mm (0.12–0.20 in)