Are these stock pistons? Oversize?

[Roadking]

My Kawasaki 750SX-A1 (1992) pistons have a circle and the number 100 engraved on their tops. Are these stock? Are the 1 mm oversized? I notice that WSM makes oversized kits up to 1 mm over, while wiseco make them larger--do the large ones require a resleeve? I only have a vernier caliper and the bores seems to be about 81 mm.
I'd like to just get new rings for the existing pistons but I don't know :clown: what kind they are and what rings would fit.
Thanks.

 

[WFO Speedracer]

Stock bore size is 80 mm so yes they are 1.00mm oversize,Pro X makes 1.25mm and 1.5mm o/s also,you can go up to 83mm before you have to resleeve.:sadwavey:

 

[thegoldenboy]

They are probabaly engraved with 1.00. Not 100. 1mm over.

 

[jeepmark4x4]

Stock bore size is 80 mm so yes they are 1.00mm oversize,Pro X makes 1.25mm and 1.5mm o/s also,you can go up to 83mm before you have to resleeve.:sadwavey:

I've heard of people going 84.5mm on stock sleeves, but you didn't hear that from me:sneaky: