MV Agusta F4 S Workshop Manual page 58

Maintenance
Twist off the plugs that close the vacuum tubes. The
number of the cylinder to which the rubber plug is con-
nected is written on the plug itself (A).
The vacuum tubes are located on the right and left side
B
of the vehicle.
Left side: Cylinders 1 and 2
Right side: Cylinders 3 and 4
Connect the measuring device with the rubber pipes.
Each pipe must match the cylinder to which it is con-
nected.
Fit in the Starter key and start the vehicle.
All bypass adjusting screws (1) must first be opened by
1
turning them 1.5 turns off the 'all closed' position.
We recommend starting from the cylinder with the
highest mercury level.
When this cylinder is taken as a reference, the by-pass
screws of the other cylinders should then be tightened
until the mercury levels have been aligned.
The following positions for the by-pass screws are
admitted: min. 0,5 turns - max. 3,5 turns.
If the lower limit is exceeded, we recommend accep-
ting a minimum position of 0.5 turns and undoing the
screw of the cylinder which had been taken as an ini-
tial reference, without exceeding the upper limit.
When idling, the revs of the engine must range
between 1000 rpm and 1200 rpm.
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