Nice M3BAR Instructions And Warnings For Installation And Use page 8

To shift the spring's attachment to different holes with respect to
the factory setting, proceed as explained below:
remove the upper cover (A) of the boom gate cubicle
1.
7
loosen the two screws fastening the cubicle panel
2.
8
8 – ENGLISH
to loosen the tension of the balancing spring:
3.
– for M-BAR loosen the nut (B) and manually turn the
spring (C) clockwise
– for L-BAR turn nut (B) clockwise
9
A
loosen the bolt (D) fastening the spring to the balancing
4.
lever
10
M3BAR-M5BAR-M7BAR
B
C
L9BAR
B
M3BAR-M5BAR-M7BAR
L9BAR
D