ok my 87 has developed this "knock" to it. Ive listened and listened and it seems to be coming right where the harmonic balancer is. Could be a rod or main I guess, but I think (and hope) its my HD. Anyone ever had this problem? Help me out! thanks! Chris
Look at the balancer for any cracking in the elastomer. And look for longitudinal run-out (the outer ring looks like someone hit it with a hammer one one hemisphere). That can cause interference issues.