Carbon build up below piston rings?polini sport!

Rebuilding my engine at the moment and was taking a look at the cylinder/piston, just wondering if the piston should have this carbon build up below the rings??Read somewhere if it it might be because the pistons have worn and it's blow past,PICS BELOW!!!!! THANKS

 

Herrs the pictures just got it out the freezer to fit back in crankcases hence the white colour and icicles!

 

The Piston rings have gone. Run your fingers around the piston top to bottom and see if you can feel any groves on it. Same goes for cylinder. If you can feel them then i would just replace the cylinder, piston and rings. Hard to tell from a picture but it looks like u have a dent in the piston aswell. But 100% i would buy new rings and a piston.

 

looks like its got quite hot too, would advise going up a jet size or 2 just to be safe. (unless maybe you just give it full throttle from cold, which would explain that)