Piston, Connecting Rod and Bearings Clean/Inspect

1. Use cleaning solvent to clean the connecting rod.
2. Use compressed air to dry the connecting rod.
3. Use cleaning solvent to clean the pistons if reusing the pistons. DO NOT wire brush the piston skirt or the ring groove area.
4. Use cleaning solvent to clean the piston pins if reusing the piston pins. New pistons contain new piston pins.
5. Use a groove cleaner to clean the piston ring.
6. Inspect the connecting rod for the following conditions:
- Inspect for twists.
- Replace if damage is evident.
- Inspect for nicks.
- Replace if damage is evident.
- Inspect for cracks.
- Replace if damage is evident.

7. Inspect the pistons for the following conditions:
- Inspect for cracked skirts.
- Inspect for cracked piston pin bosses.
- Inspect for cracked ring groove lands.
- Inspect for nicks that may cause binding.
- Inspect for burrs that may cause binding.
- Inspect for warped ring groove lands.
- Inspect for worn ring groove lands.
- Inspect for eroded areas on top of the piston.
- Inspect for worn piston pin bores.
- Replace the piston if any of the above is evident.

8. Use a micrometer and use an inside micrometer to measure the piston pin bore-to-piston pin clearance.
9. The maximum clearance is 0.003 - 0.008 mm (0.0001 - 0.0003 in).
10. Replace the piston and replace the pin if the pin bore-to-piston pin clearance is beyond the proper specification.





11. Measure the piston ring end gap clearance in the bore. Perform only after the cylinder has been honed.
12. The 1st and the 2nd compression ring gap specification is 0.30 - 0.50 mm (0.0118 - 0.0196 in).
13. Replace the piston rings if the end gap clearance is not within the proper specification.
14. The oil control ring end gap specification is 0.40 - 1.40 mm (0.0157 - 0.0551 in).
15. Replace the piston rings if the end gap clearance is not within the proper specification.





16. Measure the piston ring groove clearance.
17. The 1st and the 2nd compression ring groove clearance specification is 0.02 - 0.04 mm (0.0008 - 0.0015 in).
18. Replace the piston if the ring groove clearance is not within the proper specification.
19. The oil control ring groove clearance specification is 0.01 - 0.03 mm (0.0004 - 0.0012 in).
20. Replace the piston if the ring groove clearance is not within the proper specification.