I agree, gears would naturally be noisier than a belt but I think we could live with that.
I ran a Vincent 1000 with a Steib sidecar for 30 years and they were always known for their mechanical noise, but it was a fact that very often the noisy ones were the quickest, not that it should make any difference.
As we are aware, the engines in our M3Ws are non-interference engines, so if the gears were to fail it would not result in serious top end engine damage, and with the correct choice of gear material and heat treatment this should not be a problem.
Helical timing gears are a lot quieter and really a must. Velocette tried straight cut in the 50's when they introduced the M series. It was found acceptable on prototype engine but the thinner timing cover on production models forced them to use helical gears which solved the problem.
