Are the flyweights mounted over a pin of the flywheel ?
Is so, is the pin pushing or pulling the flyweight. With a pulling flyweight the clutch will become smoother.
Other trick is not the most fancy but works is use a more richer setting on the LSN.
But finally your finger must do the trick, do not open the throttle in one fast moment but open the throttle slowly.
Speed is only fiction but a 130+km/h MRS4 is for real.