Suzuki DF 25 Service Manual page 160

PISTON
• Inspect piston for faults, cracks or other damage.
Damaged or faulty piston(s) should be replaced.
• Piston ring to groove clearance
Before checking, piston grooves must be clean, dry and free
of carbon.
Fit piston ring into piston groove, and measure clearance be-
tween ring and ring groove using thickness gauge.
09900-20803 : Thickness gauge
Piston ring to groove clearance
Standard:
1st. 0.03 – 0.07 mm (0.001 – 0.003 in.)
2nd. 0.02 – 0.06 mm (0.001 – 0.002 in.)
Service limit :
1st. 0.12 mm (0.005 in.)
2nd. 0.10 mm (0.004 in.)
If measurement exceeds service limits, replace piston and /
or piston ring.
Piston ring groove width
Standard :
1st. 1.02 – 1.04 mm (0.040 – 0.041 in.)
2nd. 1.21 – 1.23 mm (0.0476 – 0.0484 in.)
Oil 2.01 – 2.03 mm (0.079 – 0.080 in.)
Piston ring thickness
Standard :
1st. 0.97 – 0.99 mm (0.038 – 0.039 in.)
2nd 1.17 – 1.19 mm (0.046 – 0.047 in.)
POWER UNIT 7-43
Piston ring