Far and away the hardest part is installing the new rings into the cylinder. It really helps to have a friend, so that each of you can take a side and make sure the rings are going in as they should.
1) Check your ring end gap.
Mine were about 20-25 thousandths. Rule of thumb is 4 thousandths per inch of bore, so they were a bit worn. The new rings were a little tight at ~14 thousandths, so I went ahead and filed them out to 16ish. Use a flat cross-stroke of the file so that you aren't putting an edge on, and make sure there's no burr when you're done.
2) Put the rings on the piston. This takes some patience and care... especially the oil sweeper ring.
3) Wipe off the surface where the base gasket will lie. Just get it clear of oil.
4) Lay down the new base gasket.
5) Position the cylinder, feed the cam chain hangar wire up through the cam chain tunnel.
6) Set the ring end gaps @ 180 to each other in the relief provided on either side of the base of the cylinder. Lower the cylinder on, using your thumbnails and/or a small screwdriver to keep the rings compressed as the cylinder comes over. The compression ring is usually pretty easy, the oil ring is kind of a bear. Just take your time and don't let the cylinder settle until the rings are where they need to be, it's easy to bend or break a ring at this stage.
Sorry, no pics, I was kinda involved.
Now the cylinder is settled down on the new base gasket with the piston home where it belongs. From here out, it's just basic reassembly.
7) Lay down the new head gasket
8) Feed the cam chain hangar wire up through the head, and then play your game of angles trying to get the damn thing back in. It came out, it will go back, just be patient and creative.
9) Drop the 5 bolts into place- small bolt in chain tunnel, 4 head bolts. Tighten methodically in a criss cross pattern to torque spec- see manual. You'll see there are two torque specs- the idea is to bring them up to the first one, and then go to the second, to avoid warping things.
10) Reinstall cam with dot pointing up. Install retainer, using some loctite on the retainer bolt. If the retainer threads are oily, make sure to clean them with some solvent so the loctite sticks, that would not be a good thing to have come out.
11) Reinstall shims, lifters, and lifter rods. Check valve clearance. If it moved a bit from disassembly but is still in spec, don't sweat it, they'll bed back in.
12) Unlock the engine by reinstalling thick copper washer. Turn the motor over slowly by hand using the kick start or rear wheel. If you did something wrong, you don't want to find out by mashing the starter button.
13) Reinstall valve cover
14) Reinstall thermostat, radiators, refill cooling system.
15) Reinstall header, silencer
16) Reinstall intake manifold, carburetor, fuel tank.
That's about it! It's really not that bad, if you're careful and methodical it will take a couple hours to strip everything down and have the head off for cleanup. The next night, after the head is done, put everything back together.
Holler with any questions...