-Perform idling adjustment (Pg. 18).
-Stop the engine.
-Remove the fuel tank (Pg. 46), and supply fuel for the
carburetors by some means during adjustment.
-For US model, unscrew the vacuum plugs (4) from the
manifolds, and pull off the vacuum
hoses (2) from the
manifolds sliding the
hose clamps out of position.
-Except for US model, unscrew the vacuum plugs (6)
gauge adapter (special tool) into
each vacuum plug hole, and connect the vacuum gauge
hoses to the adapters (6, 4 for US model) and vacuum
hose fittings (2 only for US model).
A. Vacuum Gauge Adapter (57001-401)
C. Vacuum Plug
-Completely close the vacuum gauge damper valves, and
then start the engine.
-With the engine running at idle speed, slowly open each
damper valve until gauge needle flutter is less than 3
cmHg, and note the gauge readings.
-Calculate three averages of each two combined carbu-
retors, i.e., #1 and
a difference of more than the specified value
between any two avarages, synchronize the carburetors
according to the following procedure.
Difference between Two Averages
under 2 cmHg
A. Damper Valve
B. Vacuum Gauge (57001-226)
To synchronize carburetors:
-Stop the engine.
-Loosen the locknuts (3) of
-Turn each adjusting screw in until it seats lightly, and
then back it out 1112 turns.
NOTE: Carburetor synchronization should be adjusted
by turning the balance adjusting screws within the range
between 112 '" 2112 turned back position. If the adjusting
screws are turned in exceeding the range, the operation
of the link mechanism may become stiff. If the adjust-
ing screws are turned out exceeding the range, the link
mechanism may have play.
-Start the engine and adjust
speed, use the balance
to alter the balance adjusting
Adjust to a difference
which is less than the specified value.
A. Balance Adjusting Screw
C. Balance Adjuster (57001-1034)
NOTE: There is only one adjusting screw to control
both butterfly valves of each 2-throat
mally there will be little or no difference between the
vacuum of each throat passage.
-Perform idle speed adjustment again
-Check that the mechanism moves smoothly without
binding. Open the throttle grip and let it snap shut a
few times. Make sure the vacuum readings stay within
the specified vacuum reading. If they do not,
justing screws may be out of the adjusting range (112 '"
2112 turned back position).
-If any gauge reading is below 14 cmHg after synchro-
nizing the carburetors, recheck the points
end of the Idling Adjustment (Pg. 18).
-After the carburetors are properly synchronized, tight-
en the locknuts without changing the positions of the
-Detach the vacuum gauges, install
and their washers (4 ea). Connect the vacuum hoses
(2) to the fittings. Slide the hose clamps back into
eG1eck the operation of the fast idle speed, and adjust
if necessary (Pg. 50).
-Install the fuel tank (Pg. 46).