Nick and Cpt
I have tried turning off the #1 and it does seem to go away. The vibe then becomes essentially steady but of much lower magnitude (just a slight, constant vertical). But changing the AP's doesn't have any effect,nor does swapping sides. (Nick you're right about the maintenance guys wanting to smother me lol). I will ask them, gently, about looking into the things you've mentioned.
As an aside, the #1 AP always always always produces a very obvious stick vibration. Very noticeable when doing the AP check after start. The cyclic just vibrates fore and aft about a 1/4 inch, kind of a buzz.
Nick, would have PMed but not as PC savvy as I thought I was.
As for the second bifilar, we were talked into just one of them 12 years or so ago when we specked out the machine. After installing it I'm sorry we didn't have it all along.
Thanks for your help.