Thanks Peter. For the novice I would suggest something simpler. Certainly a single cylinder. A casting might be okay but it too would need to be pretty simple.
Thanks bent. I did try removing the gland nut but saw little difference. I'm pretty sure it's the head cover. I remember having had trouble with a center drill on one of the covers and when I look at that one...
. When I get the gumption up, I'm going to try remaking it. Although it's a cast part, only about 1/16" of the rim shows so I think some bar stock will do.
No doubt a lot of adjustment is needed as well. I get a lot of air out of one cylinder's exhaust but not so much out of the other. After twiddling with the eccentric, I got better exhaust. But I don't think the valves are in the right place.
On the plus side, what I thought was wobble in the flywheel turns out to be the crankshaft shifting a tad left and right. I should be able to adjust that with the cranks. The flywheel itself looks pretty true.