Yamaha 2008 YZF-R6X, Service Manual

Page: 102 / 434

ENGINE
3-7
EAS20570
SYNCHRONIZING THE THROTTLE BODIES
NOTE:
Prior to synchronizing the throttle bodies, the
valve clearance and the engine idling speed
should be properly adjusted.
1. Stand the vehicle on a level surface.
NOTE:
Place the vehicle on a suitable stand.
2. Remove:
• Rider seat
Refer to “GENERAL CHASSIS” on page
4-1.
• Fuel tank
Refer to “FUEL TANK” on page 7-1.
3. Remove:
• Caps “1”
4. Install:
• Vacuum gauge “1”
• Digital tachometer
5. Install:
• Fuel tank
Refer to “FUEL TANK” on page 7-1.
6. Adjust:
• Throttle body synchronization
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
Basic procedure
a. Start the engine, warm it up for several
minutes, and then let it run at the specified
engine idling speed.
b. Turn the bypass air screw “1” with a white
paint mark out a little, and then turn it in
fully.
c. Using the throttle body that has the bypass
air screw with a white paint mark as the
standard, turn the bypass air screws with-
out white paint marks in or out to the adjust
the other throttle bodies.
NOTE:
• If more than one throttle body has a bypass
air screw with a white paint mark, use the
one with the lowest vacuum pressure as the
standard.
• After each step, rev the engine two or three
times, each time for less than a second, and
check the synchronization again.
• If an air screw was removed, turn the screw
3/4 turn in and be sure to synchronize the
throttle body.
NOTE:
• The difference in vacuum pressure between
two throttle bodies should not exceed 1.33
kPa (10 mmHg).
Vacuum gauge
90890-03094
Carburetor synchronizer
YU-44456
1
1
1
Engine idling speed
1250–1350 r/min
Intake vacuum
20.0 kPa (5.9 inHg) (150
mmHg)
1
1