I have a 1995 Polaris 300 4x4 (air cooled two stroke) that's been in our family since 1998ish and am in the process of stripping it down and fixing or replacing anything that needs attention. We've worked this little guy hard towing trailers full of firewood and plowing snow. It's been a good machine. It's mine now and it will be used at our farm property doing the same kind of work. It will never see the trails, its a worker bee only. Anyway, I'm going to redo the top end and wondering if I should do the bottom end too. How long do these things last? My thinking is its a slow turning motor. Nothing like a snowmobile, but so many starts and stops, hot and cold cycles. Must take a toll? Any thoughts?