440 indy trail

i need some help with my 1997 indy 440. i blew it up and i am having a hard time finding pistons for it. any help or advice would be much appreciated, thanks!

I got a 84 polaris 440 indy trail, I put on a set of rebuilt carbs, new recoil spring, all new fuel line, cleaned the gas tank, new plugs, has a newish cdi. After I put the carbs on I fired it up, let it warm up, then once I gave it a little gas it stalled, but fired back up, I'm guessing the...