I have a Polaris Genesis i 2002 and have found out why it's not running properly. I noticed that cylinders 1 & 2 were running fine (spark plug looks good and were heating up) but the third cylinder didn't seem to be running (sooty spark plug and not getting warm at all)

On further inspection, when I took the head off and checked the barrel and piston there are scorch marks and scratches all down the barrel. Must of overheated at some stage.

So now I need to get a new piston for it then I'll get the barrel machined to match the new piston. What piston do you recommend and where from? (Need to order it asap)