Greg they have the engine casting no issue here, I would guess the crank, rod and piston liner ok: They have to work on their tolerances
and assembly decent screws are not that much money I do not know if they are CNC or not if they do they have to learn to set it, There is no excuse for not having threads cut right and clearance for assembly and dis-assembly
they have the basics, by the way the carb seems fine except for the crummy screws holding it in martin