Just had a guy come in with blown out top end from his walmart motor - checked piston and it is 45mm, so 60cc kit. I have no parts for that, so sold him a 70cc A80 to put on the bike - he seems happy with that.
guy finally showed up with the rest of that 60cc (I gave him a price break on new motor so I could get a look at the dead 60)
guy was really happy as he'd never ridden a 66cc let alone the 70cc A80 I sold him
took it apart today and cases are about same as 49cc (short upper case bolts) but have some weird casting flaws above drive cover
it's been worked on a bunch, so am still a bit unsure of what parts it came with - has balanced crank, but with old style rotor (key closer to 1 o'clock) so matches crank slot which is also off to right
mag was newer 2-wire and all other parts were same as usual