I have a Lucas Magdyno marked M01*2 463957 L6 79. Reading previous threads the 79 is the date: September 1939. Will this Magdyno work on my 1944 BSA M20? I am fitting a October 1939 BSA M20 engine to my M20, so the magdyno is close in date for it, but is it the correct model and such? Thanks!

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I guess that as long as it is an M20 ignition, they are all the same.

I believe that this earlier thread still sums up the current state of our collective knowledge :-

http://pub37.bravenet.com/forum/static/show.php?usernum=3155626639&frmid=16&msgid=1372430&cmd=show

AC20 seems to have been the code for the various M20 mags.

Obviously, you'll need the correct mounting, pick-up away from the cylinder and anti-clock rotation.

Note that the direction of rotation is viewed from the drive end of the mag...
It should have a 'tight wire' adv/rtd cable set up as well (the cable enters the mag to the right of the contact breaker assembly and the timing is set fully advanced when the lever on the handle bar is pulled all the way to 'tighten' the cable...)

There may be code number differences but all wartime M20 magdynos are interchangeable over the various years...Ian

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

OK, from the drive end (the part that enters the engine), there is an arrow stamped on the face pointing to the right (I don't see an arrow stamped on the data plate BTW).

email (option): questmasters(at)hotmail(dot)com

Also, if I am using the correct terms, the pickup (black plastic or bakelite part) is on the right side, as viewed from the drive end.

email (option): questmasters(at)hotmail(dot)com

Could be from a 16h

If it's marked clockwise and the pick-up / HT lead is close to the cylinder then it does indeed sound like Norton - the base plate fixings might confirm this.

It might not be a bad idea to post clear photographs of each elevation so that we can see what you've got (and maybe learn something if it's an unknown variation !)

I tried to post several photos, is html code not allowed from an image hosting site?

email (option): questmasters(at)hotmail(dot)com

This is the correct reconfiguration for an M20. Norton and Royal Enfield would have the adv/rtd cable at the front of the points block and from memory Norton and Ariel have their Bakelite pickups near the cylinder.

This picture is posted via the Site that Rob Miller suggested and by using the " HTML Full Linked" from the " Embed Codes" menu.....Copy and Paste! :+1: Ron

email (option): ronpier@talk21.com

Ok, I figured out how to make the pictures post. Here is my Lucas M01*2:

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Clockwise rotation with slack wire advance is nothing I recognize from a Wartime bike. It's like a Norton mag and maybe the cam block has been changed? Rik did Norton ever use slack wire advance pre war? Ron

email (option): ronpier@talk21.com

No, Ron. They didn't. There is SCC No.2 Brown on the end plate too...I suspect that this was a Norton magdyno and that the points set-up has been swapped over but it highlights the problems of identifying the various parts - If it still has a clockwise cam then it's not going to enjoy life on an M20.

In the UK, it wouldn't be such a problem as it could probably be exchanged for an anti-clock body.

There remains a puzzle relating to the specification plate which is a few digits out from any known fitment that I can trace. I'll have another look this evening. The plates are of course all too easy to swap. I'm sure that it is a '38 - '39 platg, based on the type number range and the '2 spec as well as the date.

Nice unit, must be late '30's with those sturdy brass threaded inserts in the base...Never understood why Lucas stopped with those inserts:slightly_frowning_face:

Would also say a early Norton unit with the points-end replaced.

BR Michiel W

I don't think it's any great deal to change the rotation. You just have to change the R cam plate for L and vice versa. I fitted and timed up a refurbed mag to my own Norton 16H before I'd realized that it had the wrong rotation. I took it to my mag guy who modified it in about 10-15 minutes. Ron

email (option): ronpier@talk21.com