Help Identify Pistons?

[spazzed]

I'm working on my 1967/68 YCS1c -- It's a 180cc twin, 2 stroke. Have the heads/cylinders off and need to order new pistons and rings. Build thread here.

Can anyone tell me what these numbers indicate?

RH Piston - 597 on top and 5050 on bottom.

On inside -- IZUMI 8

LH Piston - 5degrees on top w/ an arrow and 5050 on bottom.

On inside -- 1 IZUMI

 

[stevemcqueen187]

I believe that indicates .50 overbore. 2nd overbore from stock.