G12CSR magneto removal

ajsm18 · Post by **ajsm18** » Sat Jan 15, 2011 3:48 pm

Hello,

This is my first posting here and I apologise if this is a topic which has been covered before but I can't find the answer to my problem, so here goes....

I bought my bike (1960 G12CSR but it has a 61 AJS 31CSR engine) last year with a (supposedly) reconditioned Lucas K2F magneto. However, I've discovered that the bearings are either knackered or loose. It seems to turn without roughness but there is a lot of play on the magneto shaft.

Anyway, I obviously need to have some work done on it and know a good chap who will recondition it for me (AP Magnetos, Dorset, UK) but here's the problem. How do I undo the lower of the three nuts securing the flange to the inner timing cover? I've tried all sorts of spanners, socket and box spanners but can't get onto the lower nut to undo it. Whatever I try, either the gearbox case, crankcase or engine plates get in the way. I guess there should be a special tool but can't find it mentioned anywhere. Do I need to remove the engine or gearbox to get at the nut? I hope not but am beginning to wonder!

Any help anyone can give me would be very gratefully received!

Kind regards

Mark

petert120r · Post by **petert120r** » Sat Jan 15, 2011 5:08 pm

You have to remove the timing cover first. You will find that the lower bolt head is recessed into the case but can easily be removed with a suitable box spanner or thin walled socket (1/4" Whitworth as I recall) holding the external nut with an open ended spanner of the same size. You'll also need an extractor tool (available from Jampot Spares) to remove the magneto pinion.

Your choice of APL to do the repair is an excellent one - I've used Paul many times with good results.

Don Madden · Post by **Don Madden** » Sat Jan 15, 2011 5:47 pm

It is a very tight fit to attempt to fit any spanner on the nut at the bottom. I jam a wide blade screwdriver between nut & crancase to prevent it turning until loose enough to use fingers & the reverse to tighten. Cheers, Don.

ajsm18 · Post by **ajsm18** » Sat Jan 15, 2011 6:10 pm

Hi Peter & Don,

Very many thanks for your replies. It hadn't occurred to me that I could access it from inside! I have the pinion extractor, so no problem there and should have a suitable thin-walled box spanner somewhere!

Thanks again for the advice and, yes Peter, Paul is a good guy. My '47 Model 18 AJS was transformed once he'd reconditioned the mag on that.

Many, many thanks

Mark