Not real much about Magnetos, but what he did say was true, Magnetos were expensive to make, but were reliable, till battery,coil ignition came along was cheaper to produce,so all manufacturers went down the road, as you all know I am a big fan of Joe Hunt Magnetos, yes they are not cheap but the new 4 rare earth magnets produce on of the biggest sparks around, so much better than the old 2 rare earth JHs but they were still good and the simplicity of the JHs as well Morris Magnetos, the old Maggie's from days gone by were to complicated to work on or replace condensers etc the JHs are so simple take off the front cover and the point's, condenser as well the coil is all there, simplicity at its best and so reliable for a first kick start every time, tune up kits are cheap, but over 12 years on my Norton I haven't even touched the points with over 35k miles on it, my old JH on my 81 Triumph Thunderbird clock up 250k km on it without any problems with the old JH at all and also a one kicker every time and was still going strong when I sold that bike
Most will disagree with me hangging off the side of motor but I don't care as it's simple to install, to work on if need to and so reliable, I love it.
Nigel I been saying it for a long time and I don't care what others think, hanging off the cam couter act the extra weight that's on the primary side of the motor well that's my thinking any way, + to me it's a work of art in the way they are built, why hide it behind a hot motor, hanging out in the fresh air flowing around it has to make for long life, no matter what others say, my JH on my old Triumph hanging off the side and 250k km without any problems at in the 9+ years on that bike, how long will it would have lasted behind a hot motor, may be why tho old Maggie's had troubles, who knows.
But after you run it you will be won over I am sure, I don't worry what others think where it's mounted as most have never run a JH Maggie in their lives but they all seem to be experts, not.
I’ve given up debating shut off valves. Personally I’d never use one as the risk of catastrophic failure vs the minor inconvenience, given my own memory and chance of forgetting, all adds up to make it a no go.
But the owner of this bike seriously knows his shit, and it works for him.