Ill put some pics up when I finish work to show you the pistons with the rings removed.
Hopefully I can show you the crud build up, but it potentially may disappear as I've had them soaking overnight.
These rings were incredibly stuck solid and weren't budging for anything or anyone (I work at a car garage and had plenty of mechanics trying to tackle them, with every tool and trick in the book...but no joy)
...baring in mind, the bike had potentially been sitting still for 30+ yrs.
When I got it back in april, the 1st thing I did was strip the carbs and rebuild them, and they too were jammed up solid with varnish...took alot of man hours to sort them.
So this piston issue doesnt really suprise me!
...pics to follow