TOHATSU BFT75A Service Manual page 421

dummyhead dummyhead
CYLINDER BLOCK
PISTON RING END GAP
Use the piston to push the piston ring [1] into the
cylinder sleeve and position it horizontally at 15 to 20
mm (0.6 to 0.8 in) from the bottom of the cylinder.
Measure the piston end gap [2].
STANDARD:
TOP
SECOND
OIL
SERVICE LIMIT:
TOP
SECOND
OIL
If the end gap is larger than the service limit, check the
cylinder sleeve I.D. (page 15-18).
If the cylinder sleeve I.D. is smaller than the service
limit, replace the piston ring with a new one.
PISTON PIN-TO-PIN BORE
CLEARANCE
Check the outer surface of the piston pin for damage
(scores, scratches, etc.).
Measure the piston pin O.D. at three levels.
Take the minimum reading to determine the piston pin
O.D.
STANDARD:
17.996 – 18.000 mm (0.7085 – 0.7087 in)
Measure the I.D. of each of the two piston pin bores.
Take the maximum measurement to determine the
piston pin bore I.D.
STANDARD:
18.010 – 18.014 mm (0.7091 – 0.7092 in)
Calculate the gap between the piston pin O.D. and the
piston pin bore I.D.
STANDARD:
0.010 – 0.018 mm (0.0004 – 0.0007 in)
SERVICE LIMIT:
0.020 mm (0.0008 in)
If the measurement exceeds the service limit, replace
the piston pin with a new one and recheck.
If the measurement still exceeds the service limit after
replacing the piston pin, replace the piston with a new
one.
15-20
0.15 – 0.30 mm
(0.006 – 0.012 in)
0.35 – 0.50 mm
(0.014 – 0.020 in)
0.20 – 0.70 mm
(0.008 – 0.028 in)
0.60 mm (0.024 in)
0.65 mm (0.026 in)
0.80 mm (0.031 in)
[1]
[2]
TOP
MIDDLE
BOTTOM
15 - 20 mm
(0.6 - 0.8 in)