Measure The Piston Pin; Measure The Closed Gap Of The Piston Ring; Connecting Rod Measurement - Segway VILLIAN SSV Series Service Manual

CYLINDER HEAD, CYLINDER, PISTON CYLINDER HEAD, CYLINDER, PISTON
C C
B B
A A

Measure the piston pin

◆ Measure the diameter of the piston pin in
three positions and two directions (90° apart).
If the limit is exceeded, the piston pin needs
to be replaced.
Piston pin diameter
standard：
20.000 ~ 20.005 mm(0.7873" ~ 0.7875")
limit:

Measure the closed gap of the piston ring

◆ ◆ Use the piston to push the piston ring 【B】 into
the cylinder bore 【A】.
◆ ◆ Use a feeler gauge to measure the closed gap
【C】 when the piston ring is at the top and bottom
of the cylinder bore.
TIPS
After the cylinder bore is worn and deformed, there will
be a difference between the closed gap of the piston
ring at the top and bottom of the cylinder bore. At this
time, the cylindricity and roundness of the cylinder bore
should be measured to determine whether the cylinder
can continue to be used.
If the closed gap of the piston ring exceeds the limit, a
new piston ring needs to be replaced.
Piston ring closed gap
fi rst air ring:
0.25 ~ 0.35 mm(0.01" ~ 0.014") 0.5 mm(0.02")
The second air ring:
0.35 ~ 0.5 mm(0.014" ~ 0.02") 0.7 mm(0.028")
Oil ring
0.2 ~ 0.7 mm(0.008" ~ 0.028") 0.9 mm(0.035")

Connecting rod measurement

◆ Measure the inner diameter of the small end hole
of the connecting rod. If the limit is exceeded, the
connecting rod needs to be replaced.
Connecting rod small head aperture
standard ：
20.015 ~ 20.030 mm(0.7879" ~ 0.7885")
limit:
◆ Install the corresponding connecting rod cover
(without bearing bushes), and screw in the
connecting rod bolts.
◆ Tighten the connecting rod bolts to 25Nm (2.5 kgf·m,
18.4 ft·lb).
◆ Measure the diameter of the big end of the
connecting rod. If it exceeds the limit, the connecting
rod needs to be replaced.
Big head aperture of connecting rod
standard：
44 ~ 44.016 mm(1.7323" ~ 1.7329")
Limit::
3-5-39
19.98 mm(0.7866")
standard
20.06 mm(0.7897")
43.96 mm(1.7307")
limit