[kz1000st]

There are so many factors to consider in two stroke longevity. How it's used, the oil used and how it's cooled. Most people don't keep two wheeled machines for more than a few years and don't generally put a lot of miles on them during that time. By the time the machine gets to its third of fourth owner it's been through hell. My experience is that two strokes mainly wear their rings and barrels faster because they're lubed by gas thinned oil. The lower ends are usually fine since many auto lube systems pump through the main bearings first. Everything after that usually suffers lube issues in the long term.