Later R90/6 cylinders (99mm spigot). Very nice shape. I had them measured, and they are marked.
Top: 3.546" Bottom: 3.545"
Top: 3.546" Bottom: 3.544"
These are suitable to keep your bike running with stock pistons for a while (with ~0.004 clearance), or to overbore to the first-over. With NEW stainless pushrod tubes (~$90 value). $300 plus actual shipping cost.
Or...overbore to 1000cc. I have a nice pair of 93.97 pistons if you want to do that. Pistons + machining for $400 extra (machining by Engine Dynamics in Petaluma, CA). Result will be a perfect fit and a plug-n-play 1000cc upgrade.