Two strokes have a lot of built in cooling just because of how the fuel works. Inefficient combustion so excess fuel carries heat out of the cylinder, and the excess oil also carries heat out.
Start running the af ratio lean and the cylinder temps will blow a hole through the piston. I think that'd be tough to do on an rc engine though just how the carbs are setup, your tuning options are pretty broad compared to say a motorcycle carburetor.
Aluminum melts at 1250°F, and most engines will handle spikes of temperature above that, but not for prolonged periods, and there's a zillion factors that contribute to the fate of it.