Having just made a lifting bracket (in anticipation of a Bleazey job on the Centa) and recognising that the threadings for this are the top mount for bike installation leads one to wonder (as Andy did above) that if a brace could be conceived it could damp the engine's movement very effectively - there is a lot of mass flopping around quite a long way above the soft rubber mounts so the amplitude and force of the vibration is no surprise....