Suzuki GSX-R750 Service Manual page 226

THROTTLE VALVE SYNCHRONIZATION
• To synchronize throttle valves, remove the rubber caps 1 from
each vacuum nipple and connect the vacuum balancer gauge
hoses to the vacuum nipples respectively.
[ 09913-13121: Vacuum balancer gauge
• Connect a tachometer and start up the engine.
• Bring the engine rpm to 1 200 rpm by the throttle stop screw.
• Check the vacuum of the four cylinders and balance the four
throttle valves.
The vacuum gauge is positioned approx. 30° from the horizontal
level, and in this position the four balls should be within one ball
dia. If the difference is larger than one ball, turn the balance ad-
justing screw on the throttle body and bring the ball to the same
level.
A correctly adjusted throttle valve synchronization has the balls
in the No. 1 through 4 at the same level.
#
Avoid drawing dirt into the throttle body while running
the engine without air cleaner box. Dirt drawn into the
engine will damage the internal engine parts.
NOTE:
* During balancing the throttle valves, always set the engine rpm
at 1 200 rpm, using throttle stop screw.
* After balancing the four valves, set the idle rpm to 1 200 rpm by
the throttle stop screw after installing the air cleaner box.
FI SYSTEM AND INTAKE AIR SYSTEM 4-79