1992 SL650 piston questions

[zapc]

hi sorry this is probably gonna be a long post. I was given a 92 sl650 ski in very good condition.
got it to run after lots of tweaking. checked compression and was 60,65,90 not good. pulled
cylinders and pistons, pistons have markings 45A50 on them checked bore and got 2.680,think that comes to
68.072mm. don't even see pistons that large for sale. how big can u bore cylinders, what do the piston numbers mean?

doubt it pays to resleeve cylinders, or take risk on used ones. hopefully im wrong

there is a 1994 750 for sale locally for $250 says no spark, if I cant get pistons and cylinders for mine, what exchanges
between the two.

thanks

[zapc]

no one here can help me?