Re: stupid threaded rods
Forget threaded rod. Replace them with Allen head cap screws. They will normally come in hardened, grade 8 steel and if your mount is contacting the frame as it is designed to do you shouldn't shear them unless you have something else going on. Check that rear sprocket installation as was suggested above and make sure the front mount is tight and snug against the frame also. Do not use rubber. It doesn't eliminate the source of the vibration, only transfers it to other parts, like fasteners. Stainless is pretty, but weak.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"