Necromancing this thread, I am reviving a 71 CB500 (someone shoot me) and sure enough, it had a broken clutch pushrod! I was able to source one fairly easily, but that is mystifying. I did not find any other evidence of carnage as if a broken chain got to it or anything else, just a nice clean break about 4 inches in from where it should be.
More on that bike shortly, just for your entertainment.
N.