With regard to the noise Dan I think you may have a vakid point.
Having said that, most british bikes had gears for their camshaft drives and as far as I know, Velocette were the only manufacturer to go to helical timing gears and from memoery I do not think anybody complianed about the noise from the timings sides of engines made by other manufacturers.
(Velocette were always a bit un-conventional, you only have to look at their clutches to see that).
The Vincent had 6 straight cut gears in the timing case and all but the last one (which drove the magneto) were steel.
The majority of the mechanical noise produced by the Vincent twin engine was caused by the strange cantilever cam followers that they had.
Dan states that the noise of timing gears would detract from the pleasure of driving the M3W.
I do not think this would be a major problem as it would be inaudible over the screaming bevel boxes.
