Yep, that was the final diagnosis of the "thunking" noise.

I was finally able to get my bike into the shop after a vacation and just being dang busy. At first, Mike (the owner of the shop) said he didn't hear anything, but that was when he was riding the Zed. I had to explain what I was hearing and when I was hearing it. I also had to explain the strong vibrations at 85mph which made my right hand go numb and put forearm in lots of pain.

As Mike rode the Zed at speed to feel the vibration, he realized the simplicity of the vibration problem...the chain was too tight!

Before my long-ass ride down to Durango at the end of June, I had taken the Zed to the shop to have the chain tightened and lubed. And a second time, I took it in to have the tires replaced.

Anyway, Mike loosened the chain up a bit and lubed it, since he said it was dry and voila! No more thunking noise and no more vibration.

Hallelujah!

A bit of good that came out of this problem was that Mike also said that the engine runs pretty well considering the mileage she has on her (over 42k). The fork oil needs to be changed, but the forks are fine, as well.

And that is it.