Once the oil pan was on, I was finally able to flip the engine over.
First thing first though, the remaining half dozen or so case bolts needed to be reinstalled and torqued down. Make sure to leave the starter out until you are finished with the head. The main oil feed line for the cylinder head comes up out of the block directly underneath where the starter mounts and that line still needs to be installed. Also, keep something tied around the timing chain, it sucks when that vanishes into the engine case.
I hadn't done any work to the cylinder head at this point as I had run out of workbench space. With the bottom end together, I had the space back on the bench I needed to overhaul the head. Here is as it looked before any work was done.
It was all quite normal looking, nothing to be concerned about. Just needed a good cleaning.
Here you can see the entire valve train off, springs an all. The lapping plate is visible off to the immediate right of the head.
Note, I always like to keep the valves and rockers in an order which allows me to reinstall them in the same spot they came out of. It's not necessary, but a good habit as old parts tend to wear into eachother.
The cylinder head after lapping. You'll note there's still a trace of the paint from the old headgasket on there. While the ideal would be to lapp it until that's gone, getting it to this point is fine. Scuffing from the lapping plate could be seen on all surfaces of the head, indicating it is flat enough for a good seal against the headgasket. A straightedge confirmed that.
Note, the valves are installed in that photo, though I had done the whole lapping process with the valves out. That's preferred as the lapping compound can be best cleaned out afterwards. Also, After the head lapping, I lapped the valves, installed new valve stem seals and reinstalled all the valves. This was just the first picture I got after tearing the cylinder head down.
Pistons were in good shape if not covered in a lot of carbon. A before and after photo.
Once the pistons were cleaned, I went about quickly honing the cylinders with an appropriate sized ball hone I had bought years ago for my first EX engine project. I got lucky and there was no pitting in the cylinder walls, which is not uncommon on the higher mileage engines. Now, technically, you're supposed to actually measure the cylinders to know if they are within tolerance. However, I have found that if you drop new, standard sized piston rings (or oversized rings if the last rebuild required boring out) and the ring end gap is within factory tolerance, that's just fine for a street ridden motorcycle. FOG has a while thing about knurling pistons and buying oversized rings and filing down the end gap. That'll be a personal decision you have to make if you decide to go that route.
With the ring end gap checked on all the new rings, they went onto the pistons, pistons went onto the connecting rods and then the dance of dropping the cylinder jugs onto the pistons while making the piston rings compress and play along with only 2 hands commenced. Took about 10 minutes of fiddling but all the rings eventually compressed, allowing the jugs to drop into place.
Note, don't forget to install the cylinder base gasket before dropping the cylinder jugs down. It's not fun when you need to do that twice because the base gasket is still on the work bench. Also, don't forget to put a thin film of oil on the cylinder walls before doing any of this.
Once the jugs are in place, rotate the crank several times to make sure nothing is binding up. There will be some resistance, but not much. If the crank is fighting you, a piston ring may have become damaged. Take it apart and inspect if so.
Then, set the engine to TDC (it's in the manual, which you should have read the engine section a great many times at this point). Setting the cams to the correct timing can be tricky, so expect to pull the cams several times to adjust the timing by a few teeth. It's important to stick your finger in the cam chain tensioner hole to push the slack out of the chain when doing this. If you don't, it could be a tooth off and you might not notice. Once the cams are set, lather all the bearing surfaces and the cam lobes with fresh engine oil to prevent a dry start and reinstall all the cam bearing caps. They're all stamped with a different letter and the manual tells you where they go, then finally reinstall the cam chain tensioner.
Once all that's done, set all the valve clearances. It's always easier on the bench than in the bike.
I don't have any photos of reinstalling the clutch assembly, water pump, or stator side of things. That's fairly boring and straightforward anyways, plus there's a hundred walkthroughs of those procedures floating around on the site.
Here's the engine ready to be reunited with the frame. The valve cover was looking rather sad from surface corrosion, so I used the best looking one out of my stock of spares and dressed it up with Toddlamps PAIR block off kit. If you want one, go to the For Sale section there, he still sells them. It's the best you'll find and I will shamelessly advertise his stuff anytime I get the chance.
Up next, the long awaited reassembly.