So I got this '81 CM400 from my uncle, and I fixed it up and had it riding. Then it died because the cam chain broke. I opened it all up and the tensioner and guide were way chewed up. I figured that meant the chain was way too stretched, and got snapped. But then I looked down the cam chain channel and saw the chain had rubbed a groove up and down it.
So I figured that meant the chain wasn't tight, but too loose and it shook into two pieces.
I got the new chain in, new head on, adjusted the chain, and the bike runs like it used to. But I don't want history to repeat itself, so what kind of play should the chain have on the cam gear?