Monster 659 Owner's Manual page 93

Secure the tank to the subframe with the screw (14) and the
E washer (15).
Tighten the screw (14) to a torque of 10 Nm ±10%, using a
5 mm Allen wrench to counterhold the threaded insert (M)
located on the upper part of the tank.
Important
The threaded insert (M) is not present in the USA
version.
92
Lower view
14
Upper view
15
M
fig. 93