You can set the UAQ DM.Steer.Trq or Driver.Steer.Trq to zero using Direct Variable Access (DVA) or RealTime Expressions. For example type the following command in the Maneuver Commands window:
Eval DM.Steer.Trq = 0

If you set the UAQ Driver.Lat. passive = 1, it has no influence on the simulation in MotorcycleMaker. The reason is, that this UAQ is intended to deactivate the lateral dynamics of the IPGDriver in CarMaker but not in MotorcycleMaker.