True "nailing", not a valve tap, is usually an air leak problem. By all means, check your settings again but I expect you will still have the nailing. Look for leaking fuel which will be accompanied by an air leak.

If in the course of your adjustment, you have opened the fuel system by removing the hard fuel lines or changing fuel filters, you will have introduced air into the system. You can bleed the air by any number of methods but I think the OM616, like my OM617 is self-bleeding. Over the next couple of hours of driving, your clatter should lessen and go away.