Sorry, guys, I am getting sick. Felt like crap. The generator is mounted to the left side of the bike chain and seat stay tubes at three points and supported by the axle nut. The generator itself has rubber feet that I think does a good job with vibration noise. It fits snug into the mount and I secure it via two 450lb cam straps used for motorcycle transport.
I guess to explain the reason for this possibly fruitless quest is that this is a hybrid with plus and minuses from gas and electric. One of the minuses of gas is noise. An ebike is deadly silent and great cuz you can have conversations, do vlogs, and listen to earbud music (if allowed). I like to get this generator to an absurdly low noise level.
Here is what i've done so far; its not much. Hard to find free polysterene and materials.
* Lined inside of panels with felt = ~5dB reduction
* Quick check placed a 1/4" plywood board on free facing side = ~0dB reduction
This reduction is according to my video editing software and an approximation. 5dB is barely noticable to the human ear but I guess if you are really paying attention to it you will pick up the difference...
Quick idiot test. I put a plywood board infront of generator with felt on inside. With and without board. Notta