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.
Maybe you should include Moto Guzzi as well although I'm sure I could find others. I appreciate the axial load issue but in a former life I sold many helical gear conversion kits based on that of the OE V7 Sport model (see below), to owners of later models that were fitted with a timing chain. It was assumed this was on the grounds of cost saving. We never had any load issues, indeed I road nearly 100,000 miles on one bike fitted with these gears and without issue, although the original design was to accommodate such.
The lower gear drives the oil pump.
