A rubber mounted HD frame is a whole different animal than a solid mount. The whole drivetrain, engine, tranny, and swingarm/rear wheel assembly is a solid unit. That powertrain unit is then mounted to the frame at 3 points, a big rubber doughnut in front, and rubber mounts at each side of the swingarm pivot. The stabilizing links are to limit motion to a vertical plane, i.e. front to back and up and down. Without them there would'nt be anything to keep the rear wheel aligned. The reason they did this is because if you just rubber mounted the motor alone, there would still be tons of vibes transmited to the chassis through the drive chain or belt. So they just let the whole works shake on its own. When the Twin Cam softtails were developed, HD found it easier/better for that particular frame to develop a new, counterbalanced motor for it, the TC88B (for balanced) which IMO they should have done 25 years ago anyway. So to give you my take on it, it would be really tough to come up with your own rubber mounting system and have it be very effective. HTH
