Cylinder head removal.

I'll toss out a few things regarding  valve-stem seals.  I replaced mine with the typical Black generics about two years ago. I didn't use the VITON for the extra $ as I knew they wouldn't be salvageable  when I decided to do a top-end rebuild in the near future - (currently apart for that).   I was surprised to find one that had split from top to bottom and the bottom retainer clip was off.  Several others had small splits.  All of them  had  "toughened" up significantly ! 
I have the VITON type coming and based on this one experience I would NOT use any of the Black ones.
That "mystery fibers " .I'll toss this out as well,  from a similar experience:  Those fibers could be from Paper Towels being used to wipe-off  parts.  Cheap paper- towels are horrible for shedding their fibers.   I don't use them for wiping off any parts. It's probable that a P.O. used paper towels to wipe out the cam cover and to soak up the oil trapped on top of the cyl-head.  Do this a couple of times and I can easily see a significant amount of fibers finding their way into the oil-pan.  This may account for the accumulation of other debris on the screen - the fibers and other material forming a matt across the screen.  Something to consider, at least.
Good luck with the rest. 

Got word from my machine shop that I need all new valves.  Guides are OK.  Still waiting on whether the pistons can be reused.

 

McZee wrote:

The red and green pieces look like bits of old gasket sealant, strangely the black stuff is bit of leaves, as in off a tree. There also seemed to be a lot of fibers in there which looked a bit like animal hair. The only explanation I can think of is that someone in the dim and distant past has filled it up with old contaminated oil. I have now removed the valves, and some of them took quite a bit of pressure before they popped off the spring retainer. I don’t think I would have managed without a valve spring compressor. The old valve stem oil seals looked in pretty bad shape, one of them wasn’t even there. Took the springs out and there was no oil seal to be seen, no wonder the poor old thing burned oil.

Does the oil breather hose go to clean or dirty side of air ffilter? Either way, running without a filter could allow crud into the crankcase

Does the oil breather hose go to clean or dirty side of air filter?

Between the filter and carbs.

I'm traveling so don't have time to research all the pics and what not.. 
But here's a link to engine rebuild. Perhaps some pics will help you.
candybuttorg.ipage.com/cba/node/180

Hi all.Still beavering away with the top end rebuild on my big old Zed. I’ve got the cylinder head back on and the cams refitted . The sump is back on with a new gasket so hopefully it will be oil tight now. I wanted use some gasket sealer but my son says that’s not been necessary since Freddy Flintstone’s time. Some thoughts from the resident boffins would be appreciated on this subject. While I have the bike up on the bench I stripped out the clutch for inspection as it has been a bit sticky recently, especially when started up from cold. It turns out that some of the clutch plates have somehow stuck together, I renewed the friction plates on that clutch just last year, so  I have no idea how that has come about.  I’ve now  got them soaking in oil ready for rebuild.  

As long as the mating surfaces are clean and in good condition, I never use a gasket sealant - in fact, I always grease my gaskets before installing so that they never need to be replaced.