aligning the magneto.

[matchbox500]

Can anyone tell me how I ensure that the Magneto shaft and sprocket is aligned close to the alloy drive casing on my 51 G80 Rigid. I have been told that there are elongated holes in the base plate which allow the magneto to slide toward the chain case.

[wilko]

The maggy platform has only up and down play for chain adjustment, the different offset for the sprockets does the alignment.

[matchbox500]

I have correctly positioned the sprockets with the biggest offset to the top, however the chain still catches slightly on the alloy case. Are there elongated holes or even two sets of holes on the magneto mounting platform or under the magneto, to allow some movement of the mag.

[MikeM.]

The four bolt holes on the mag platform are slotted giving about a quarter of an inch movement.

[clive]

There are indeed elongated holes in the mag plate which allow you to move the mag backwards and forwards in relation to the alloy casing (only by about 1/4 of an inch). However you want it up close to reduce water etc getting in the back. Only reason to move it backwards and forwards is if the chain line is out. As far as I am aware there were no different offsets for the sprockets, except the difference between the off set for the mag spocket and the timing pinion sprocket which are different by 1/4 inch or so. The problem you have with a 51 Matchless is that the mag will be mounted behind the engine. The mag platform for these mount either side of the engine plates without a spacer. Undoing the bolts and removing the studs will still not allow you to remove the mag as it fouls the alloy casing as you try to lift it up enough to get the platform off the engine plates. You have to take the inner timing case off too. Make sure that the timing pinions do not come off with the inner or your will have to reset the valve timing. That same case also stops you getting the dynamo out without taking the primary chaincase inner off too. This was the reason the mag was eventually moved forward of the engine as with the AJS.

[clive]

beat me to it mike

[wilko]

I don't recall the slotted holes on the platform so my apologies. Think i'll go and check mine with a dentists mirror?With great dexterity you can assemble the maggy on to the platform without the timing case off, by fitting the 1/4 inch bolts last, but patience is a virtue!!

[matchbox500]

Sorted !!. The holes are elongated and moved the mag over 3mm.

[Peter Lecompte]

Hi Jim, I am just putting my magneto back onto the platform. It is a 1949 AJS rigid, so it is mounted on front of the engine. There are 2 spacers which I need (010822 and 010821). Would someone have the dimensions or know where i would find them?

Thanks Peter

[RayRST]

Peter from the parts list and measured on my 1948 16M the dimensions are as follows

010821 Front
113/16" long, 13/16" OD, stud 3/8" Dia

010822 Rear
1" long, 13/16" OD, 5/16" Dia stud

Hope this helps