Gilera SATURNO BIALBERO 350 Workshop Manual page 58

CYLINDER - PISTON 8 - 2
DISASSEMBLY
Remove the head group, gasket and rubber anti-vibration devises, as
described in section 7.
Remove the water pump, found on the left of the cylinder (fig. 1).
Remove the thermostat's housing on the front of the cylinder (fig. 2).
Lift the cylinder by hand. If necessary, use a plastic or rubber mallet to
break the seal (fig. 3).
After having removed the cylinder, cover the opening of the crankcase
with paper or clean cloth, then remove the gudgeon pin lockring (fig. 4)
and slide out pin using special tool 19.1.20530 as a punch.
If necessary use a mallet (remember to support the piston on the other
side) (fig. 5).
Remove the base gasket of the cylinder and the rubber O-ring, found
around the oil feed line (fig. 6).
INSPECTION
After a thorough cleaning of all parts, all components must go through a
careful visual inspection. Replace all parts that show sign of damage
and/or wear. Careful attention goes to cylinder wall, piston surfaces,
rings and gudgeon pin, with no signs of scoring, deep grooves,
shrinkage or any other damage.
Cylinder
Measure bore diameter (with a micrometer) at three different heights
and at 90° to one another (one measurement must be parallel to the
gudgeon pin) in order to see excessive ovalisation and taper.
If excessive wear is noted, both cylinder and piston must be replaced
(fig. 7).
Max. taper = 0.02 mm
Max. ovalisation = 0.01 mm
Piston
Piston diameter is measured at 90° to the gudgeon pin and again at 12
mm (350cc) and 7 mm (500cc) from the base of the skirt, using a
micrometer (fig. 8).
Min. clearance (service limit) = 0.1 mm
8 - 2,1