what does STANDARD size mean?

[Warren]

With rod bearings, what exactly is STANDARD? .50 mm?

 

[hawkeye18]

Um, I don't know about mm clearances, but standard bearings are the same size the engine came from the factory with. If you haven't ground down the crank round, you only need the standard size.

 

[rubydist]

and .50mm means .50mm undersized from standard - as in the crank was reground .50mm smaller.