what are your symptoms?
if the rings are worn, the engine would still run, and fire fine, but you'd have a shit ton of smoke
if it's misfiring, or you have no compression, do a wet compression test
if you still don't have compression, the problem is in your head
those engines are put together like a burger king toy, you could pop the head off in an afternoon, take it to a machine shop and have the valve seats checked, and put a new gasket on. honda headbolts are even reuseable, doesn't get any easier
just make sure the engine's at tdc when you pull the head off, leave a screwdriver in your crank, or mark it with a sharpee, the cam has a line on it to line up, so that's not a problem, besides, those sohc honda engines aren't interference anyways, you wont break anything if you're off by a degree or two, and then you can do a timing check once the engine's running
get crackin, johnny walker