I have been researching the issues on the forum and the Beta is over 50% heavier than the Perkins. The new gearbox is also a lot chunkier. As a result it shouldn't come as any surprise that the engine vibrates as it does. The old mounts as well as being old clearly wouldn't have been designed for the weight of the Beta.
With regard to new mounts, is it just a case of dividing the engine/gearbox and frame weight by 6 and using that figure to spec the mounts?
Mark & Nicky Barter