Capital engine damage?

Hey hey I just recently bought my first motorcycle and it was a KTM Duke 620 e 1997 and I’m also very excited about it. The motorcycle is obviously in a top condition and looks real as if it was just off the factory. Now my joy didn’t last long, after about 250 km I noticed during the ride that the engine brakes out a little and then runs out with a loud bang… I tried to start it again until I noticed with a look down on it The engine is also fixed. Oil is still in it Can I now assume a captial engine damage or is there still a chance to save it? Did I have to have the engine completely kicked out or revised? That would be rather uneconomical but would not like to chew. Greetings