VESPA GTS 250 I.E. Workshop Manual page 135

Vespa GTS 250 I.E.
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 FALLS INSIDE THE CYLINDER, THE
LESS THE BASE GASKET IS TO BE APPLIED (TO RECOVER THE COMPRESSION RATIO) AND
VICE VERSA.
Name
shimming
shimming
shimming
ENGINE 250 SHIMMING
Measure A
3.70 - 3.60
3.60 - 3.40
3.40 - 3.30
Engine
Thickness
0.4 ± 0.05
0.6 ± 0.05
0.8 ± 0.05
ENG - 37