I have an 82 Shovelhead that I can not get the o-ring seals on the ends of the rocker arms to stop leaking. i have changed them 4 times and after a few hundred miles and a run of between 50-70mph they are leaking again. The motor has 12,000 original miles and only seeps at a couple of the oil hose clamps. I am running 60wt Valvoline in her now. Any suggestions appreciated.