There isn't a factory sportbike made that will pull 6th gear, or 5th for that matter. Some may pull 4th with someone who knows how to use weight/ power to help out.

Dirtbikes, etc. are different because they have lower gearing throughout the gears and high torque/low rpm engines. Most sportbikes are the opposite, with long gearing and high revving engines.

A turbo R1 is most likely close to 300 HP minimum, and possibly MUCH higher. That kind of power is completely unusable on a bike like that.