Well, my '79 DOHC is on its second 630 chain (22k miles on the odometer). No issues. Not sure why your bike had problems, other than maybe the chain was stretched, or something was mis-aligned.
1979 CB750K (sold, 2012, but not forgotten)
1983 Kawasaki 440 LTD Belt Drive (sold, 2011)
1993 Kawasaki Voyager XII
Locked
