As suggested-----first have replacement stem on hand---Honda has high quality short rubber ones available, not cheap. Break bead, big water pump plier works, fish old stuff out, install new stem----as high mileage rider still in shape to check straight stem, I like to stay away from fancy 45 degree stuff, not designed for your bike that might rub on something, etc! Too bad modern scooters do not have easy to remove rear wheels (except one model BMW) and spare(nobody)