How do I install a new piston with 21 loose needle bearings around the wrist pin in the little end of the connecting rod? I have tried to install the wrist pin but the needle bearings keep falling out.

1 Answer 1


A light weight grease can be useful to keep the needle bearings in place while completing the assembly. It will provide lubrication and eventually be worn or be washed away by the normal lubrication system.

  • Would assume this is a 2-stroke engine which uses the oil in the gas mixture to lubricate things. I agree with your methodry, but would suggest using petroleum jelly as the light weight grease. Commented Nov 5, 2022 at 1:05
  • 2
    Another possibility is assembly lube. Some brands are relatively "sticky" and work well for this sort of thing. Assembly lube is also formulated so that it eventually gets dissolved and washed away by engine oil.
    – jwh20
    Commented Nov 5, 2022 at 1:43
  • +1 for engine assembly lube. The exact tool for this job - does a very good job of sticking things where they need to be and then shears very easily when used Commented Nov 7, 2022 at 18:28

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