Yeah, my bike is 42 yo. Parts are scarce and expensive.
Just got stimied on the engine rebuild. Found a couple of split, rock hard o-rings. Did manage to locate them. Had to order. $6.05 for 4 orings, the largest is 23x2.8.
Gotta have 'em. Otherwise, it'll leak like a screen door on a submarine. So, I wait for a few more days. Naturally, these are the first parts to install on the rebuild and the last on the disassembly.