push rods colors

[france320isco]

what are those colors (red, yellow, etc) that are stamped on the push rods? (they are coloured circles).

[Mr Deagle]

The connecting rods?

They are the weight groups that the factory uses to match rods.

[france320isco]

The connecting rods?

They are the weight groups that the factory uses to match rods.

Yes excuse me, the connecting rods!!
Why do they use to do that?
Can the connecting rods weight be so different?
Does it affect the engine balance?

[GeoS]

The colours show the size of the big end bore for the con rods:

Red: 52.000-52.008 mm (2.0427-2.0475 in.)
Blue: 52.009-52.016 mm (2.0476-2.0479 in.)
Standard: 52.000-52.010 mm (2.0472-2.0476 in.)

[france320isco]

The colours show the size of the big end bore for the con rods:

Red: 52.000-52.008 mm (2.0427-2.0475 in.)
Blue: 52.009-52.016 mm (2.0476-2.0479 in.)
Standard: 52.000-52.010 mm (2.0472-2.0476 in.)

Thanks...And what are 2 red balls next to the little bore (piston pin) + 2 red balls next to the big bore (so 4 red on one side) + 2 yellow ones on the other side, one on the con rod cap and the other very close to the first on the conrod?