38
402102.01
Service manual VF4 VF5
Fit the piston rings in the cylinder bore and check that the open-
ing between the ends is within the recommended values; if this is
not the case, replace the cir-clips.
Cylinder compression piston ring gap
I piston ring gap
0.20 ÷ 0.35 mm
II piston ring gap
0.60 ÷ 0.80 mm
Scraper ring gap
0.25 ÷ 0.50 mm
Check that the outer diameter of the pistons corresponds to the
recommended figures; if not, replace the piston complete with
piston rings and gudgeon pin.
Piston outer diameter
Grade A
81.920 ÷ 81.930 mm
Grade B
81.930 ÷ 81.940 mm
Grade C
81.940 ÷ 81.950 mm
Measure perpendicular to the gudgeon pin axis, 9 mm from
the lower edge of the skirt.
Check that backlash (1 a) between rings (1b) and the seats in
pistons(1c) corresponds to the recommended figures.
Cylinder compression piston ring
I piston ring
0.105 ÷ 0.150 mm
II piston ring
0.050 ÷ 0.090 mm
Scraper ring
0.030 ÷ 0.070 mm