I recently bought a yz85 in great condition it just needed some carburetor work (the float needle did not seat properly). Now that that's fixed, I have a question. The bike is an '06 and the owner said "yeah it's still on the stock piston probably only has about a hundred hours on it" I cringed when he said this. But, nevertheless, I took a test ride and decided to buy the bike. When I kick it over, the compression is average for an 85 and it starts 2nd or 3rd kick cold and first kick warm. When riding it, there are no strange noises and I can hear no piston slap or anything out of the ordinary (listen to it in this video: https://www.youtube.com/watch?v=nx0VislGsg4&t=4s). I know a top end rebuild is a must on these 2 strokes so how has this bike lasted 12 years and still sounds like it's new? It doesn't bog, the only thing I have noticed is that it will hesitate while taking off sometimes when it's hot. I know I'm going to get the average "PUT A NEW TOP END IN IT NOW" 2 stroke guru, but is it really necessary? I have not taken the cylinder off yet but I put my finger over the spark plug hole and kicked it over and it has enough pressure to lift my finger but it's also really oily in there (oil ring left on my finger). So, what do you guys think? Does she got a few more hours or does it need a new piston ASAP?