Hi Rik

Your photos interested me, in that my mag pick up is as shown on the left hand photo, but I have a slack wire advance.

Therefore, I thought that I had a post war mag (not that it bothered me too much).

Confused!

Regards

Pat

email (option): sacombsashtrees@hotmail.com

£720 is an expensive 'chance' to take....The fact is it may work OK or it may not...

However, if you already have a magdyno that doesn't work, you can have both units fully reconditioned using modern rewinds etc. etc. for quite a bit less than that...

So do ya feel lucky?... ...Ian

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

Pat it could be slack wire if it's Royal Enfield. For some reason RE had seen the light before the others and adopted slack wire through the war. On the other hand it could still be tight wire on a mag that drives the opposite way as on Norton's for instance.

I know you're not bothered, but you would only need to change the cam box on the end to make it tight wire. (Slack wire is actually a better idea)

Ron

email (option): ronpier@talk21.com

The position of the pick up can't be used as a guide as to whether a mag is 'slack' or 'tight' wire advance...

The relevant factors are a combination of the direction of rotation when running and the entry position of the adv/rtd cable to the points end housing...Ian

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

Hi Ian and Ron

I didn't explain my query very well, in that on my M20, the mag pick up is as on Rik's left hand photo, suggesting that my mag is a late 30's to mid 40's mag. However, my mag has slack wire advance, which I thought meant that it was more likely to be post war.

Regards

Pat

email (option): sacombsashtrees@hotmail.com

As Ron noted it could be a WD Royal Enfield mag..Or a 'BSA' early mag body with the later points end casting fitted (they are interchangeable)...

All wartime BSAs were 'tight' advance...

People have got up to allsorts over the years... ..Ian

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

Patrick, both the mags in the photo are machined with the pickup in the same place - on the opposite side to the engine. Nortons were odd in having the pickup close to the cylinder - maybe warm and dry but a bugger to get at.

Nortons had clockwise mags with cable entering on the left for tight-wire advance and their points assemblies are quite hard to find as they were often cannibalised in the 1950s and 1960s to provide slack-wire advance on the anti-clock mags used by the majority such as BSA.

I still hear of Gold Star owners looking for Norton type assemblies as they're all afraid of their temperamental beasts ending up on full advance by accident.

The only difference between 'early' and post-war mag bodies is the casting with that 'dip' or cutout along the top face where the dynamo sits.