PIAGGIO 633823 Service Station Manual page 144

Engine
By working on two fitted cylinder head fixing nuts,
nut and lock nut, as shown in the photograph, re-
move the stud bolt from its seat.
Clean the threaded seat on the carter thoroughly.
Refit a new stud bolt and apply the special product
on the threading crankcase side.
Tighten up to the depth of the driving indicated.
Recommended products
Loctite 'Quick Set' Strong 270 threadlock
Strong 270 threadlock
Lubrication
Conceptual diagrams
LUBRICATION CIRCUIT
ENG - 58
MP3 250 i.e.