hey mike,How many miles are on the bike?1st thing is why it needs a new sub?did he flip it?yes it could be repaired(tig welded) if not too bad but a clean 100.00 special is better.as far as inspecting the bike,check the normal wear items.tires,brake pads & rotors,oil level & color,brake fluid color.another good check is to push the bike forward in neutral & grab the front brake to check neck bearing cond.if the bike has been endo'd or heavily wheelied they are usually pretty loose and can feel or hear the play in the neck.check the handlebars,ends,and footpegs also for signs of ground zero.it sounds like a decent deal, you just need to be careful out there with so many bikes being used hard these days!good luck lmk,Anthony