Suzuki DF 25, Service Manual, Page: 91 / 148

POWER UNIT 6-25
Piston ring to groove clearance
Before checking, the piston grooves must be clean, dry and free
of carbon.
Fit the piston ring into the piston groove, and measure the clear-
ance between the ring and the ring groove using the thickness
gauge.

09900-20803: Thickness gauge
Piston ring to groove clearance:
Standard:
1st & 2nd 0.020 – 0.060 mm (0.0008 – 0.0024 in)
Service limit:
1st & 2nd 0.120 mm (0.0047 in)
If the measurement exceeds the service limits, replace the pis-
ton and/or the piston ring.
Piston ring groove width:
Standard:
1st & 2nd 1.21 – 1.23 mm (0.048 – 0.049 in)
Oil
1.51 – 1.53 mm (0.059 – 0.060 in)
Piston ring thickness:
Standard:
1st & 2nd 1.17 – 1.19 mm (0.046 – 0.047 in)
Piston ring end gap
Measure the piston ring end gap with the piston ring in the low-
est position of the cylinder bore.

09900-20803: Thickness gauge
Piston ring end gap:
Standard:
1st & 2nd 0.15 – 0.35 mm (0.006 – 0.014 in)
Service limit:
1st & 2nd 0.50 mm (0.020 in)
If the measurement exceeds the service limit, replace the posi-
tion ring.
Piston ring
1st ring
2nd ring
Piston ring