My 748's done 41000 miles now, in 3 years.
What do you mean by "major"? To be honest, I don't see why it shouldn't run as long as any other motorcycle engine, as long as regularly serviced etc.
Apart from consumables like rectifiers and clutches
(actually not *that* bad on that score), nothing's really gone wrong. The rockers were pulled at the last major service. One was replaced; all the others were fine. I was told that the cams still had the parkerising coating fully intact on them. On that basis, I don't imagine there's any serious engine wear to the bores, etc. Certainly it uses only a negligible amount of oil.
Of course, it's yellow, so that probably explains my relative lack of problems.
