Alert! Loose bolts...
I was running my 5-100 and it was developing more vibration. I shut it down and spotted a hex bolt on the floor. It was from the front timing chest. The other bolts were quite loose! I cleaned everything off and reinstalled the fallen bolt and tightened all of them up. Vibration gone. I checked my new 7-35 and the front bolts were loose there too! Check your bolts folks!!! -Tom