Here is a pic of the camera mount I made. I had everything I needed laying around the garage. If you had to buy everything my guess would be 6 or 7 dollars.
The PVC Tee I cut in half with a hacksaw, drilled a hole in the stopper/cap the size of the bolt, the black wing nut thing (not sure what they are called, a wing nut would work just as well) is to lock the camera in place. To make the cut halves of the tee to fit tight I cut a piece out of an old inner tube and wrapped the crossbar then clamped the Tee around it. To keep bolt tight I just ran a nut down the length of the bolt and tightened. Just look at the pic, it's so simple I only make it harder by writing about it.
Don't know the size of the bolt, I just found one that fit my camera.
This was inspired by a leaky water line in the house one night. Minus the bolt of course. Wrapped the pipe with rubber, and clamped with a split piece of pvc.
Rubber isolation for the handlebar mount! Gad, that's great. I'll have to try that on my Ram mount. It's been pretty shaky with just foam on the camera mount plate. At least, on the Uly it's shaky. Especially under 4K RPM.
Thanks! Of course, I feel really stupid for not having thought of it myself. But at least somebody did, and posted it where I was reading. Now, where's a piece of rubber lying around here? Hhhhmmmmm.