Over all the years that Harley has been making bikes, coming up on 113, they only started to use the "cush" drive in '08 on their touring only bikes. Their cruisers, Dynas etc, still have the same bolted solid sprocket to rear wheel as before.
Japanese and probably European bikes have been doing it since the '50s or '60s.
I had ridden my friends Softail Deuce the few months before I bought my '08 Road King and boy was there ever a difference between the two.
You wouldn't think that the Goldwing is setup with a cush drive, but they are. Within the driveshaft there is an inner and outer shaft/housing and the two are connected with a rubber sleeve inside the tube. This gives just enough cushion to take the torque pulses out of the system.
In a V-Twin, the torque/firing pulses are very noticeable and that's what give the trans all the problems. That's why Harley has a compensator on the motor to isolate the pulse vibrations from the trans.
In the stock M3W intermediate drive compensator assembly, they have a rubber donut of sorts that does the last coupling between the flywheel and the compensator; at least that's what's shown in the parts catalog.
I remember my old BSA Victor 441 single, when I was on gravel roads or loose dirt, every firing pulse of the motor created its own little divot in the dirt from the back tire chunking. This was more noticeable in a higher gear and lower speeds with the cracking of the throttle.
I've always thought that M3W could just stack about four of the rubber donuts together and use that as the isolator instead of the compensator. Actually the rubber donut looks very similar to what I've seen on eBay for the rear of the BMW sedan driveshafts. They bolt between the rear u-joint flange and the third member flange. This give it a bit smoother feel.
BMW isolator:
Toyota isolator in a more refined manor:
Either of these could be stacked to provide more or less "cush" and I believe would be more than enough on the M3W.
