Action Fours' cams were not terribly hard. This was good with the rockers in these bikes, but not necessarily good for long life. Their published comment (that I remember) about the extra clearance was about "...letting more oil flow under the rocker foot on the lee side of the lobes..." to help keep things lubed and cooled. This makes sense, although it also makes noise: Honda has always been big on trying to make the engines very quiet, sometimes even to their detriment.
