Magneto removal

Information relating to the Matchless G12 or AJS Model 31 650cc twin
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ChrisTheChippy
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Location: Essex

Magneto removal

Post by ChrisTheChippy »

As per title.
My next task is to remove and get the magneto sorted.
My problem is I have looked at the owners manual and the instructions for mag removal seem very sketchy. Probably because it's a very simple task but I'm just not getting it.
If I may just ask a couple of questions to get it sorted in my mind .
I have removed the timing cover and have the magneto removal tool from the club.
I know I use it to pop the mag from its taper but do I need to loosen the 3 bolts that hold the magneto body on ? Or does that come after ?
An idiots step by step guide would be very useful plus any hints and tips most welcome.
I feel a bit thick but I'd rather be embarrassed than damage the magneto.
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clive
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Re: Magneto removal

Post by clive »

As I remember now the timing cover is off its undo the nut holding the magneto gear on and then use the removal tool to pull it off the taper. Once that is off you need to undo the three retaining bolts and remove. However one of the nuts is stupidly difficult to get to. Someone else on here gave a hint for replacing which was to cut a screwdriver slot in one of the bolts and then in the inaccessible place put the bolt in from the back. Put a nut on the thread and then use the screwdriver slot to hold the bolt steady whilst doing it up. There is enough clearance behind the magneto gear for the nut rather than the bolt head. Not sure that is a clear guide.
clive
if it ain't broke don't fix
ChrisTheChippy
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Location: Essex

Re: Magneto removal

Post by ChrisTheChippy »

Thanks clive . That's much clearer now. You have cleared up the niggling worry I had in the back of my mind about damaging the magneto.
I have read that one of the fixings is a bugger to get to so thanks for the tip on refixing . This is probably some way down the road yet but I had the thought of welding a socket to the end of a flexi pipe spring. Probably a daft idea but hey ho I will try anything once .
ChrisTheChippy
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Re: Magneto removal

Post by ChrisTheChippy »

Bugger posted twice !!!!!!!
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clive
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Re: Magneto removal

Post by clive »

ChrisTheChippy wrote: Thu Nov 17, 2022 10:51 pm Bugger posted twice !!!!!!!
Not any more!

Not sure the flexi spring thing would work as the spring would tend to allow the socket to rotate. I found it relatively easy to insert the bolt the wrong way and then an easy job to do up the nut. The screwdriver slot allows you to get the thing tight enough with a spanner that the bolt does not rotate, before you finally tighten with a socket, all done from the outside except the insertion of the bolt. You do need to have the correct bolt so it does not project too far.
clive
if it ain't broke don't fix
Groily
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Re: Magneto removal

Post by Groily »

On my less-accessible lower fasteners, I have soldered short lengths of brazing rod on to the nuts, so I can hold them (reasonably) easily up behind the crankcase when refitting the bolt (and then tightening at the head with a slim socket). It has taken the sting out of it for me.
A ground-down open-ender with the nut glued in the jaws can help if doing things the hard way.
(An intelligent child with delicate digits can also be useful if it can be spared from chimney-sweeping duties.)
ajsph
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Re: Magneto removal

Post by ajsph »

I have fitted a helicoil in the lower point on the magneto, 5/16x 26, now I only have the bolt, and the magneto is easy to remove.
Poul
ChrisTheChippy
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Re: Magneto removal

Post by ChrisTheChippy »

Thanks for all your replies and tips!
Magneto safely removed now. That bottom bolt is a bu###r to get to! At first I was a little bit stumped until I worked out I was able to get a slim spanner up from below in the small gap between the engine and the gearbox. Just about got on the nut then was able to hold it while I got the same thin walled socket I used to undo the head nuts ( thanks club spares) on the head of the bolt and undo it . So all good . When it comes to refitting I'm going to do a little judicious bending of the spanner and stick the nut in with silicon . I've done this before on other things and if it's done the day before it holds just ,long enough to get a start on the thread and is easily removed.
Pouls idea of a helicoil is a good idea. Think I might be a bit worried about messing it up though. When you consider how often they have to come off the stress might not be worth it !
bitza
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Re: Magneto removal

Post by bitza »

I posted a while ago, saw a slot for screwdriver in head of the lower bolt, then using a slim cobination spanner to hold the nut,you can screw up said bolt , not forgetting the spring washer I know it's a b----y fiddle, after nipping up tighten it with the socket from mag gear end, the idea of tack welding or brazing a short length of rod to the nut seems a good tip.
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