Folks, I may have missed this but it's important to stress that using a tool to hammer in the push-rod seal collar only applies to what, pre-1977??? bikes. After 1976??? the collars were brazed in place and hammering on them will make things worse.
I believe that tapping in those collars was a reasonable solution on earlier bikes but no solution at all on later bikes.
I know some of you know the precise dates so I'll leave clarification to yous.
I just don't want anyone with a late model airhead thinking they can resolve pushrod tube seal seeping with a hammer. For those bikes the ONLY solution is seal replacement.
Am I wrong?