Check at cold, find TDC, remove cam cover and line the mark on the cam sproket with the mark on the top of the opening, remove the little plastic plug on top of the engine cover right behind the pull start, there should be an 'F' or a 'T' lined up with a mark inside the threaded hole. Make sure the chain is tensioned properly, use a feeler gauge, cold intake valve play, .0024-.0039 in, cold exaust, .0063-.0079in. Don't worry about special tools, a couple of wrenches, or pliers for the square bolt. That should be it. I don't want to be a damper, but I had the same problem, ticking getting louder, everything was ok. Turned out my head was warped and one of my valve guides was broken, ticking was loss of compression from a mal aligned valve and head gasket. The valve guides ARE replaceable, don't need a new head. Also, if you can, cheack the wear on the cam sproket, but it does sound more like valve play, hope this helps...
