Hey guys as I posted in another thread, I recently purchased my first chain saw and learned a big lesson. . (Don't buy a used chainsaw off Craigslist unless you know what your looking at. .) I bought a stihl 029 super that I found out after that it's motor is blown. Well I am taking it apart to put a new motor in it (49mm) and I got a glimpse of the piston and I wanted to see if you guys could offer me insight on what could cause this damage? Because I don't want this to happen to me, I want to learn. Thanks guys!