PIAGGIO Beverly 500 i.e., Workshop Manual

Page: 113 / 382

Inspecting the piston
- Measure the outside diameter of the piston, per-
pendicular to the gudgeon pin axis.
- Take the measurement in the position shown in
the figure.
Characteristic
A =
43.2 mm
Piston diameter:
92 mm
- Using a bore meter, measure the inner cylinder
diameter at three different points according to the
directions shown in the figure.
Characteristic
Standard diameter:
92 + 0.018 +0.010 mm
- Check that coating is free from flakes.
- Check that the head matching surface exhibits no deformations or wear.
Characteristic
Maximum allowable run-out:
0.05 mm
- Pistons and cylinders are classified into categories based on their diameter. The coupling is carried
out in pairs (A-A, B-B, C-C, D-D).
- 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.
N.B.
MEASURE THE CLEARANCE BY INSERTING THE BLADE
OF THE FEELER THICKNESS GAUGE FROM THE SECOND
SEAL SIDE.
Beverly 500 i.e.
Engine
ENG - 113