Hello,

Does anyone have a photo of the mounting location for the late version of the main switch on a 1945 WM20 that you could post? Much appreciated.

email (option): steve.l@shaw.ca

This? Ron

email (option): ronpier@talk21.com

Hi Ron, yes thats exactly what I'm looking for.

email (option): steve.l@shaw.ca

Here is the wiring diagram Steve....if you need it. Ron

email (option): ronpier@talk21.com

Do we know the reason for the change from the headlight switch? Some operational reason? It's hard to see what economies would be gained from it.

It does away with the ampmeter which is expensive to make and there may be less wire? which would add up over thousands of machines.

Rob

email (option): robmiller11(a)yahoo.co.uk

They saved the cost of an ammeter and maybe some wire. Ron

email (option): ronpier@talk21.com

Could there be other reasons?

It was a period when all new machines were being made ready for the far east and the invasion of Japan, were ampmeters quickly damaged by humid conditions?

How often did the average DR look at his ampmeter? only when the lights stopped working, at which point the unit fitter would step in with his tester anyway?

Rob

email (option): robmiller11(a)yahoo.co.uk

We were typing at the same time Rob. But considering the wiring. There is only one wire heading along the tank tube to the headlamp, instead of the usual 3. So overall thousands of yards saved. Ron

email (option): ronpier@talk21.com

Ha, you are all wrong here, the official report was, that most electrical failures were caused by failure of the wiring loom, the chafing of the wires around the headstock, and getting nipped by girder fork spring, and the often very dusty/muddy road conditions, were very hard on the wiring loom, and ammeter, so that is exactly why the under saddle switch was invented, it reduced the amount of wires going to the headlamp, and hence less problems, came a bit late in the war, but still a good idea!

Cheers,

Lex

email (option): welbike@outlook.com

I think the 'rocker' switch used in the headlamp is the same as the dip switch used on late B44s, B50s....or at least very similar..Ian

email (option): ian@wright52.plus.com

email (option): robmiller11(a)yahoo.co.uk

Ian,

Does that one also has a P in white engraved on the top? I never see them much at jumbles, so think the postwar ones are different.







Rob,

It's written in the "Motor Cycle" of around November 1944, as an official WO modification, but cannot find (for some time now), the whole 1944 stack of those issues, might have lent them out I fear, but I remember the text from the article very well, have written it down but in Dutch, will translate and post it here later. Last August I went through all of the other wartime magazines, both the Blue un and the Green un, and found one article from 1943, that dealt with the same problem, but it's not the one we need, some friends are building late war machines, so I wanted to give them all the info, hopefully it will be found soon.

But two pictures of the wiring diagram for the under saddle switch attached here.

Cheers, Lex

email (option): welbike@outlook.com

The later switch doesn't have the 'P' engraved on the top (Rons doesn't either)..However, the switch works in the same way...They aren't overly common but I've seen them for sale and sold one myself at a jumble a couple of years back......What does the 'P' indicate?....Ian

email (option): ian@wright52.plus.com