Ok so HRC in developing the 04-05 1000RR for race use added a new linear link to the suspension that alters the rising rate of the swingarm to make it less progressive. While this is an improvement over the original link it is not the same level of improvement we typically see on aftermarket race links.

The amount of change is so small that you don't even need to change to a different spring rate when installing this new linkage. Does it work? Yes it does, but don't think this will be the same night and day difference like on the RC51 or Duc 1098 platform etc. In fact the linkage design change is so minor that the link HRC designed for the 04-05 racebikes became the OEM linkage for the 06-07 CBR1000RR Production Bikes.