Replace the piston if scratches or seizure is evident on its surfaces (especially the thrust surface). Replace the piston if it is cracked.

1. Insert the piston pin into the piston pin hole with your thumb. You should feel a slight resistance. Replace the piston pin if it can be easily inserted or there is an excessive play.

2. The piston and piston pin must be replaced as an assembly.

1. Check the piston ring for damage, excessive wear, and breakage. Replace if defects are evident. If the piston has been replaced, the piston rings must also be replaced.

2. Check for clearance between the piston ring and ring groove. If it exceeds the limit, replace the ring or piston, or both.
Standard value:
• Number 1: 0.03 - 0.07 mm
• Number 2: 0.02 - 0.06 mm
Limit: 0.1 mm

3. Insert the piston ring into the cylinder bore. Force the ring down with a piston, the piston crown being in contact with the ring, to correctly position it at right angles to the cylinder wall. Then, measure the end gap with a feeler gauge.
   If the ring gap is excessive, replace the piston ring.
Standard value:
• Number 1: 0.20 - 0.30 mm
• Number 2: 0.30 - 0.45 mm
• Oil: 0.10 - 0.40 mm
Limit:
• Number 1, Number 2: 0.8 mm
• Oil: 1.0 mm

1. Remove oil from the crankshaft pin and the connecting rod bearing.

2. Cut plastic gauging material to the same length as the width of the bearing and place it on the pin, parallel with its axis.

3. Install the connecting rod cap carefully and tighten the nuts to the specified torque.

4. Carefully remove the connecting rod cap.

5. Measure the width of the plastic gauging material at its widest part by using a scale printed on the plastic gauging material package.
Standard value: 0.02 - 0.05 mm
Limit: 0.1 mm