Ian, I recall you saying to me that there was another problem with the design of the bevels, that they were exactly 2:1 ratio. Accordingly the same teeth on the crown wheel were in contact with the same pinion teeth which resulted in wear not being distributed evenly and caused the noise/whine. Was this an issue? If so, it's unlike the pre-1931 two speeders that had bevels of usually 13:33. They usually growl a little, but don't seem to get noisier as the revs increase.
