Honda BF40D Manual page 184

• PISTON RING THICKNESS
1) Check the piston ring for damage (scores, scratches, etc.).
2) Measure the piston ring thickness.
1
2
Top
3
Second
4
The oil rings are the combination rings. Replace the side rails
and the spacer as a set when either the top or second ring
5
needs replacement.
6
• PISTON RING-TO-RING GROOVE CLEARANCE
Install the piston ring on the piston properly. Push the piston
7
ring in until it is flush with the outer surface of the piston, and
measure the piston ring-to-ring groove clearance.
8
9
Top
10
Second
11
Oil
12
If the measurement exceeds the service limit, replace the
piston ring with a new one and recheck.
13
If the measurement still exceeds the service limit after
replacing the piston ring, replace the piston with a new one.
14
• PISTON RING END GAP
15
16
Top
17
Second
18
Oil
19
• PISTON PIN O.D.
20 1) Check the outer surface of the piston pin for damage
(scores, scratches, etc.).
2) Measure the piston pin O.D. at three levels. Take the
minimum reading to determine the piston pin O.D.
Standard
17.994 - 18.000 mm
(0.7084 - 0.7087 in)
10-11
Standard Service limit
0.975 - 0.990 mm 0.960 mm
(0.0384 - 0.0390 in) (0.0378 in)
1.175 - 1.190 mm 1.160 mm
(0.0463 - 0.0469 in) (0.0457 in)
Standard Service limit
0.040 - 0.065 mm 0.100 mm
(0.0016 - 0.0026 in) (0.0039 in)
0.015 - 0.045 mm 0.100 mm
(0.0006 - 0.0018 in) (0.0039 in)
0.055 - 0.140 mm 0.150 mm
(0.0022 - 0.0055 in) (0.0059 in)
Standard Service limit
0.15 - 0.30 mm 0.80 mm
(0.006 - 0.012 in) (0.031in)
0.15 - 0.30 mm 0.80 mm
(0.006 - 0.012 in) (0.031 in)
0.20 - 0.70 mm 1.00 mm
(0.008 - 0.028 in) (0.039in)
Service limit
17.954 mm
(0.7068 in)
[1]
PISTON RING
[2]
END GAP
[1]
TOP
[3]
BOTTOM
184
[2]
MIDDLE