Interesting stuff if you’re into this kind of thing. It’s not that uncommon to find that someone has tinkered with an air-cooled engine without being aware of some unusual and subtle requirements. That being the case, you never know what you’re going to find when you go in for a simple valve adjustment, as in this instance.
It’s pretty much impossible to see, but the rocker shafts and are out of position. A bit easier to see, the head studs are also out of position, making torque-checking difficult but fortunately not impossible (yet).
There’s also silicone-like goo in here, apparently to prevent oil leaks.
Spark plug heat range is also important, and these are not the right ones. That doesn’t account for why one of them hasn’t been firing, but it’s important nonetheless.
All of this must be (and will be) sorted out before Adam can then do the standard stuff.
