A little more background on the testing of engines. I have sold equipment to GM back in the 80's and 90's which was used to test their engines, specifically the 3.8l V6 which, at the time, was considered by the engineers to be the best engine GM ever built.
GM tests individual components such as cams and crankshaft assemblies for service life under various operating conditions(load, speed, temperature). They also test complete engines to destruction to find weak points and to determine manufacturing tolerances. Parts like cams and crankshafts have service lives of over 1,000,000 miles when operated with the specified oil change intervals at engine temperatures between 180 and 220F. The internal parts of a production engine should be good for 350,000+ miles which in most cases is longer than the rest of the vehicle.
Based on what I have been told by the engineers I have worked with, I am not surprised that a K bike engine is capable of running at red line and full load for 24 hours. I would be surprised if it wasn't.