is your cylinder wall all groved up or did you just burn a hole on the piston????
depends on how much work your gonna have to do, maybe just a piston.ive burnt a hole in a piston before and thats all that happend, but if your rings came unseated you may have dug up your cylinder wall...post some pics of the inside of your cylinder...run your finger in it..how does it feel..rough or smooth?if not then your gonna have to bore it.
remember also..if you burn a piston up,,the broken material has to go somewhere !!! obviously it all goes down !!! ansd some out your exhaust. if it were me i would be splitting the case to give it an inspection, but if youve never done that, than atleast give it a good flushing, several times !
BTW mrbrocco....how did that port job turn out..i see you havent responded to kenedy at all, im curious of how it run after you bolted it up
also...you DO NOT need to bore a cylinder every time you do a top end rebuild...lol..rings will wear long before a cylinder wall does...you can add a new piston, fresh set of rings and a new gasket set as long as you havent had a piston burn up, rings come unseated and scratch up a cylinder...ive done many a top end rebuild without boreing....all depends on how your cylinder is...take a micrometer, check it out/....see what shape its in, do a good inspection if you know what your looking for
now...the "the leak down test"...when ya get it all back together again make sure ya get the carb boots on clean and tight, make sure the reed spacer is clean and tight, good new gaskets on everything. whenever ya do a rebuild ALWAYS use new gaskets..start your engine and let it idle...grab a can of startting fluid(ether)...spray a little bit near your intake boots and around all your gaskets and around your crank case..(dont go overboard, it only takes a little...if theres a crack, leak or hole anywhere your engine will start to idle irractically imediatly...there ya go, ya just did a leak test and saved yourself a hundred dollars without taking it to a garage....I worked for a outdoor powersports dealer for a few years and thats all we ever did...it works everytime