I will first point out that most of these factors can be corrected, with enough effort.  KuryAkyn or any other plastic or metallic grip will not work.  Grips with no flange at the outboard side may slip more than you like, but usually work fine. The collar must engage soft, grippy rubber.  Handguards that attach between the weight and the grip are right out. Some old Piaggio scooters, which have no handlebar inside their throttle sleeves, cannot be fit with our throttle locks.