Well it's still my contention the main reason 200's burn up the top ends is because of the roller bearing mains .The carbs have been blamed but I'm not really certain if that's the main cause .
There is no earthly reason other that an air leak or runnng the carb set extremely lean for those things to cook the piston and cylinder .
So now I wonder and if my supposition is correct if periodically those bearing should at least be checked for side slop .Early or timely replacement of those things might add increased life to these things for a fraction of the cost of other repairs .Just a thought .