Did (another!) top end strip last night, still trying to fix that damned top end oil leak. Only manifests at prolonged high rpm, so really only when cruising at 75mph... hence it gets moved all over the place by the wind! It's definitely coming from the head or base gasket joint, but damned if I know where exactly!
Having tried red hylomar and steel shim head gasket up top, and oiled paper gasket below twice now, I'm reverting to a method used on my old 125/215cc race-spec engine (another air-cooled 2-valver), which used no gaskets, just blue hylomar. Ran fine for thousands of miles. In this case I'm forced to keep the steel shim head gasket at least, due to the already narrow squish measurement. Loosing both gaskets would knock 0.2mm of the squish, taking me to about 0.7mm, which is a bit close for comfort. Just loosing the base gives my 0.8mm which I'm more comfortable with.
Just bolted the head down, giving it an hour or so to settle before re-torqueing.
Oh, and I also learned that the two tiny machine screws that hold the lock together for the left-side panel are M2.5 threads. If one falls out, then the latch on the lock is free to rotate, and your panel tries to make a bid for freedom.... as I discovered a few weeks ago. Caught panel, but only just got round to finding new screws. This time I'm bond the buggers in place!