Inspecting The Piston; Removing The Piston - PIAGGIO Fly 150 4T Workshop Manual

Fly 125 - 150 4T
- The pistons are oversized due to cylinder rectifi-
cation and are subdivided into three categories
1st, 2nd, 3rd with 0.2-0.4-0.6 mm oversize. They
are also classified into 4 categories A-A, B-B, C-
C, D-D.

Inspecting the piston

- Carefully clean the seal housings.
- Measure the coupling clearance between the seal rings and the grooves using suitable sensors, as
shown in the diagram.
- If the clearance is greater than that indicated in the table, replace the piston.
Name
Top piston ring
Middle piston ring
oil scraper
MAXIMUM ADMITTED CLEARANCE AFTER USE
Name
Top piston ring
Middle piston ring
oil scraper

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
020430Y Pin lock fitting tool
STANDARD COUPLING CLEARANCE
Description Dimensions
0.025 ÷ 0.070
0.015 ÷ 0.060
0.015 ÷ 0.060
Description Dimensions
0.080 mm
0.070 mm
0.070 mm
Initials Quantity
Initials Quantity
Engine
ENG - 111