PIAGGIO Beverly 300 i.e., Service Station Manual, Page: 160 / 333

Studs
Check that the stud bolts have not worked loose
from their seat in the crankcase.
Check the depth of stud bolt driving with a gauge,
as indicated in the picture. If it varies significantly
from the driving depth indicated, it means that the
stud bolt has yielded.
In this case, replace it.
Engine
Beverly Tourer 300 i.e.
ENG - 160