Removing The Piston; Choosing The Gasket - PIAGGIO MSS Fly 50 4T Workshop Manual

Engine

Removing the piston

- Install piston and wrist pin onto the connecting
rod, aligning the piston arrow the arrow facing to-
wards the exhaust.
- Fit the pin stop ring onto the appropriate tool.
Specific tooling
020448Y Pin lock fitting tool
- With the opening in the position indicated on the
tool, set the lock ring into position in the tool with
the punch.
- Rest the tool on the piston paying attention that
the 90°chamfered side faces upwards as indicated
in the figure.
- Fit the gudgeon pin stop using the plug.
CAUTION
USING A HAMMER TO POSITION THE RINGS CAN DAM-
AGE THE LOCKING HOUSING.

Choosing the gasket

N.B.
MEASUREMENT "A" TO BE TAKEN IS A VALUE OF PISTON RE-ENTRY, IT INDICATES BY HOW
MUCH THE PLANE FORMED BY THE PISTON CROWN FALLS BELOW THE PLANE FORMED BY
THE TOP OF THE CYLINDER. THE FURTHER THE PISTON GETS INSIDE THE CYLINDER, THE
THINNER THE HEAD GASKET TO BE APPLIED SHOULD BE (TO RECOVER THE COMPRESSION
RATIO) AND VICE VERSA.
Characteristic
Shimming system to control the compression ratio
CR: 11.1 ÷ 12.9
Name
shimming_1
shimming_2
ENG - 90
PISTON PROTRUSION CHECK
Measure A
0.05 ÷ 0.25
0.25 ÷ 0.40
MSS Fly 50 4T
Thickness
0.35
0.25