Dommie mag removal

Previously John Shorter wrote:

There are numerous posts, on this subject. Try searching "Mag removal".

Thanks John. I did try searching but I came to the conclusion that perhaps I was searching the wrong way. Every result that I looked at seemed to be comments and replies to earlier posts and most of them referred to how you should modify your spanners to undo the dreaded bottom nut. I have already loosened the bottom nut and removed the timing chest, I just need reassurance on what to do prior to removing the automatic advance and drive mechanism. I keep finding references to timing marks 12 links apart but I do not fully understand the process.

Appreciate your interest, thanks again Ron

Previously john_baron wrote:

The top two fixings are studs from which the nuts are easily removed. The lower fixing is a small bolt and nut which are difficult to access and only perseverance and maybe a bit of grinding of your spanners will remove them. Use of a mirror may help. Removing the timing cover so you can access the lower bolt head inside is necessary. The advance and retard from the end of the mag will need undoing but I'd leave this until you have removed the lower bolt in case you want to abandon the process and you will near enough retain the timing.

Many thanks John, if you see my reply to John above you will see that I have already got to the stage where I want to remove the drive assembly but I am not sure that I have got the hang of guarding the timing settings. I have locked the engine on TDC on the left firing stroke and I want to know what I should do before removing the mag drive. Many thanks for your interest and input. Regards, Ron

Previously john_baron wrote:

Hi Ron, if all you are doing is removing the magneto you won't disturb the cam timing and you can't put the magneto chain on in the wrong place. You will have to re-time the magneto points when you refit it, normally done by fitting a timing disc on to the crank left hand side and using a cigarette paper to tell you when the points are just opening. You cannot use a bulb and battery across the points because of the internal magneto wiring. You will find re-timing instructions and degrees BTDC in any Norton manual. I did all this just last week so it's fresh in my mind . Good luck but you need any, it's fairly straightforward.

Cheers, John.

That is just what I wanted to hear. I had got it into my head that it was necessary to make or use timing marks to be sure that the mag went back in the exact orientation that it came off from. If I can just remove the chain, no matter what position the points are in, and then re time it when it is reinstalled I am a happy bunny. Much appreciated, thank you Ron

Previously paul_standeven wrote:

You may find that a tube spanner gives best access to the lower magneto nut.

Not part of magneto removal, but I have fitted a BSA A10 extended magneto nut to that concealed lower mag stud. The nut extends beyond the points housing, and makes access for adjustment or removal easy. When you fit a mag and intend to use one of these special nut,, place in on the engine plates before installing the magneto. Put it on the studs, then offer up that special extended nut. It's a really useful accessory.

I have also fitted an A10 carburettor drip tray so that any drops of petrol leaking from the carb don't go near the sparks department

Paul

Thanks Paul, your advice is most welcome. Regards Ron

Previously ian_cordes wrote:

Ron. It sounds as though you do not have a manual. That is where you will find the step by step guide to mag removal. Buy one and all will be revealed!

Thanks Ian. I have got a Haynes workshop manual but I wasn't very impressed with the mag removal section. Can you recommend a good manual? Thanks and regards Ron