Added weight behind the trailer is not what the trailer frame is designed for. That extra weight is flexing the trailer frame much more than it was designed for. A toy hauler (which that is not) is designed to carry the extra weight closer to the axles, but certainly not behind the trailer. As you have experienced, transporting an 1100 pound motorcycle (plus the weight of the platform it is resting on) is not a wise thing to do. As a Harley owner I understand the desire to have the bike with you. For safety's sake though, make different arrangements. I would think about a toy hauler.