Here is a link to the Ohlins 2WD system (that is what they call it). It uses hydraulics versys chain/shaft that Christini uses, but it is slightly heavier. It was fairly successful in the Dakar rally, even though it was mounted on a 450cc bike against larger competition. It won a few stages, mostly in wet conditions. They also installed it on a Yamaha R1 street bike and found it ran faster lap times even on dry pavement!?