Thank you for the info.
That engine is truly a spectacular example of a DL 50, and probably needs to be torn down, mic'd, and blueprinted/reverse engineered to find out why in the world it is so extraordinary. No joke.
You evidently have the PERFECT combo of bearing tolerances, ring fit, cylinder size, rod bearings, and carb (not to mention about a dozen other things)...no kidding!
One in a million!!!