Gas was 3 days old. I'm not really worried about why it blew up.... . I ran that thing probably 5kms, WOT in 8inches of slush and 1ft of powder doing maybe 30km/h... It overheated I'm 100% certain. I had to make a homemade piston pin puller yesterday to get the piston pin out.. It was in there pretty good.. Got it out however without any problems..
Old Man: Thanks for the advice on the replacement piston, I was actually going to order a Wiseco or Vertex (This is what I've used in the past with my 2-stroke dirtbikes).. But I'll stick with OEM or SPI in this case.
I'm assuming the numbers imprinted ontop of the piston are related to it's size? (ie standard, .30 over, .50 over) I'm fairly certain it is, I'll have to cross reference that number before I order a new one.