TOHATSU BFT115A Service Manual page 482

CYLINDER BLOCK
PISTON RING GROOVE WIDTH
Measure the piston ring groove width.
STANDARD:
TOP:
SECOND: 1.240 – 1.250 mm (0.0488 – 0.0492 in)
OIL:
SERVICE LIMIT:
TOP:
SECOND: 1.25 mm (0.049 in)
OIL:
PISTON RING SIDE CLEARANCE
Install the piston rings onto the piston so it is almost
flush with the piston outer surface. Measure the piston
ring side clearance.
STANDARD:
TOP:
SECOND: 0.050 – 0.075 mm (0.0020 – 0.0030 in)
SERVICE LIMIT:
TOP:
SECOND: 0.13 mm (0.005 in)
If the measurement exceeds the service limit, replace
the piston ring with new one (page 15-18) and recheck.
If the measurement still exceeds the service limit, also
replace the piston with new one (page 15-15).
PISTON RING END GAP
Measure the piston ring end gap (1) 15 – 20 mm (0.6 –
0.8 in) from the cylinder bottom.
Before measurement, be sure to set the ring (2) in the
cylinder squarely using the piston.
STANDARD:
TOP:
SECOND:
OIL:
SERVICE LIMIT:
TOP:
SECOND:
OIL:
If the measurement exceeds the service limit, replace
the piston ring with new one (page 15-18) and recheck.
If the measurement still exceeds the service limit, also
inspect the cylinder sleeve I.D. (page 15-33).
15-34
1.230 – 1.240 mm (0.0484 – 0.0488 in)
2.005 – 2.025 mm (0.0789 – 0.0797 in)
1.25 mm (0.049 in)
2.05 mm (0.081 in)
0.040 – 0.065 mm (0.0016 – 0.0026 in)
0.13 mm (0.005 in)
0.20 – 0.35 mm (0.008 – 0.014 in)
0.50 – 0.65 mm (0.020 – 0.026 in)
0.20 – 0.70 mm (0.008 – 0.028 in)
0.6 mm (0.024 in)
0.75 mm (0.030 in)
0.8 mm (0.031 in)
TOP
SECOND
OIL
(1)
(2)
15 – 20 mm
(0.6 – 0.8 in)