piston sizes???

[bens250ex]

im thinkin of putting a new top end piston and rings in my r so it would be fresh but i dont know what size i should order i was told it was a 262 so what size piston would that be? also is there a way i can find out to make sure what size it is if i take the cylinder off?

[quad9]

look on top of the piston, the size is stamped on it.