Wow, lots of people around here getting their feelings hurt lately.
My first guess would be compression. Due to the fact it overheated could have sealed or siezed the rings into the piston causing it to lose enough compression to not fire. Very easy to test, so I would do that first.
But, when I get a used bike, first I do is take it apart, clean it the body, clean the carb (including check the reeds), check the ignition, pull the flywheel, clean around it, check that the timing is on, check for crank seal leak behind the flywheel, and then after that is all said and done, give it a fire.
I've spent too much time trying to start vehicles off the bat and waste my time my feet and I do agree, if you have to pushstart a vehicle, there is something wrong. I don't recommend it, but if you got the energy of youth, go for it.