Damon Kirkland Option (per John Aylor):

A rubber mounting system for the early H2 cases, elegantly simple, but takes a bit of work.  Works well for the guys that don't want to find late cases or tear their motor apart.

The stock holes are drilled out to 5/8", and then sleeves are fitted over the motor mount bolts to tighten down against the frame mounts. Approx 1/8" inch is removed from each motor mount boss for "movement" clearance. The remainder of the space around the sleeve and cases is taken up by rubber tubing. He has done both of his H2's and he says you can't tell they are rubber mounted without knowing what to look for.

Drill out the mounts first with a 1/2", and then the 5/8's. Just be careful to drill straight, especially the upper rear mount, because you can cut into the "oil space". Then cut a bit of a chamfer with a 3/4".  Damon uses the damper rubbers from the instrument mounts.

Here are the pics. Be NICE, they are prototypes! I didn't have time to make a special cutter, or freeze the rubber. The sleeve is just mild steel in 1/2", and I had to center drill it to 13/32nds so the motor mount bolt would go through.  Then I machined the rubber tubing to 5/8ths leaving a 1/8" thick "washer" at the ends.

And finally, as I said before, there are many ways to rubber mount. I know this isn't the best way, but it is the simplest I have found so far, and the least work. And I don't know if it will work, but I will try. As I said, if I can reduce the "vibes" 10% I will be happy........
Damon says it makes a world of difference.