Yamaha YZF-R1 2020 Service Manual page 117

Vacuum gauge
90890-03094
Vacuummate
YU-44456
5. Install:
• Air filter case
Refer to "AIR FILTER CASE" on page 7-5.
• Fuel tank
Refer to "FUEL TANK" on page 7-1.
6. Check:
• Throttle body synchronization
a. Start the engine, warm it up for several
minutes, and then let it run at the specified
engine idling speed.
Engine idling speed
1200–1400 r/min
b. Check the vacuum pressure.
Difference in vacuum pressure
between the cylinders
0 kPa-1.3 kPa (0 mmHg-10
mmHg, 0 inHg-0.4 inHg)
If out of specification → Adjust the throttle
body synchronization.
Adjusting the throttle body synchronization
1. Adjust:
• Throttle body synchronization
a. Start the engine, warm it up for several
minutes, and then let it run at the specified
engine idling speed.
Engine idling speed
1200–1400 r/min
b. Using the throttle body that has the bypass
air screw "1" with a white paint mark as the
standard, adjust the other throttle bodies
by turning its bypass air screw in or out.
PERIODIC MAINTENANCE
ECA21300
NOTICE
Do not turn the bypass air screw (white paint
mark) of the throttle body that is the stan-
dard. Otherwise, the engine may run roughly
at idle and the throttle bodies may not oper-
ate properly.
TIP
• Turn the bypass air screw using the carburetor
angle driver.
• After each step, rev the engine two or three
1
times, each time for less than a second, and
check the synchronization again.
• If a bypass air screw was removed, turn the
screw in fully and be sure to synchronize the
throttle bodies.
• If the throttle body synchronization can not be
adjusted using 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).
Carburetor angle driver 2
2. Stop the engine and remove the measuring
equipment.
3. Install:
• Caps
• Service hose cap
4. Install:
• Air filter case
Refer to "AIR FILTER CASE" on page 7-5.
• Fuel tank
Refer to "FUEL TANK" on page 7-1.
• Rider seat
Refer to "GENERAL CHASSIS (1)" on page
4-1.
3-10
90890-03173
1