I'm currently rebuilding a '79 Garelli Super Sport XL engine. The flywheel-side main bearing cage was missing; I found the majority of it in the tailpipe. The 6203-size main bearings are quite common and the rod bearings were spared any damage, but I'm wondering if the jug can be bored (chromebore?) and whether any piston kits are available that would fit.
Amazingly, the existing piston and cylinder bore is still marginally usable, even after passing all that metal. Can't feel any scoring in the jug, the piston is a bit chewed but still makes 0.015" cold clearance at the skirts. Tough little engine. I wouldn't feel comfortable running it at 50:1 though, it would have to be a mosquito killer if I can't put a new slug in it.
Thanks for any info,