Inspecting The Piston Rings - PIAGGIO MP3 400 i.e. Service Manual

MP3 400 i.e.
- Using a bore meter, measure the cylinder inner
diameter at a given height according to the direc-
tions shown in the figure.
Characteristic
B:
43 mm
Standard diameter:
85.8 mm nominal value
- 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).
N.B.
REFER TO THE «SPECIFICATIONS» SECTION FOR THE SIZES OF THE CYLINDER AND THE
CYLINDER-PISTON COUPLING CLEARANCES.

Inspecting the piston rings

- Alternately insert the three sealing rings into the
cylinder, in the area where it retains its original di-
ameter. Using the piston, insert the rings perpen-
dicularly to the cylinder axis.
- Make sure that each single sealing ring evenly
adheres to the cylinder liner. If it does not, this
means the ring is worn. Replace it.
- Measure the opening (see figure) of the sealing
rings using a feeler gauge.
Engine
ENG - 57