Dominator magneto removal

'Tis a pig to remove! I ground the sides on an open ended spanner, and was able to undo the nut one flat at a time. There may originally have been a special spanner made for this job, but, I guess you will have to adapt your own. You have my sympathy! John

Replace it with the long magneto bolt designed for this location. It is about 6" long & extends beyond the mag enabling plenty of spanner clearance.

Dell Boy

Available from any pre-unit BSA spares stockist. Gordon.

Mike,

Check out http://www.draganfly.co.uk/shop/pd-428630541.htm?defaultVariants={EOL}&categoryId=146

Tony

Previously wrote:

Hi Mike, further to my previous comment, you may find my post, on Thorspark, of interest. I see you have received several suggestions, about fitting the B.S.A. long bolt, but, your problem was getting the mag off! John.

Previously wrote:

Thanks to all for your replies

I had thought of using the extended bolt when I had the mag off last year but it looked like the cranckcase would prevent it from fitting....

...off to get my grinder. Spanner not mag!

Hello Mike If you Look On Ebay Vintage tools and look for a snail brand 7/16ths open ended spanner you will find at this does the job well as they are a short spanner , hope this help , your anna j

Hang on, a 7/16 whitworth spanner is .710" across flats. That seems way too big for the nuts holding the magneto on. Are we sure that Anna didn't mean a 5/16 whitworth spanner, .525" across flats?

On my '54 Dommi, the correct spanner is 3/16ths whitworth, I would assume all the K series magnetos used the same size nuts. Check before you buy a useless (for this purpose) spanner! John.

I use a worn 7/16" spanner (box end), cut short so it clears, I personally dont like the long BSA nut (bolt), looks odd to me. To clarify the wrench size,that'sactual7/16", in other words, 7/16" across the flats, NOT 7/16 Whitworth. It fits nicely in the tool roll since it is so small. Anna also mentioned a 7/16" wrench (she never said Whitworth).

Skip Brolund

Blimey Skip, the long BSA mag bolt just makes work on the bike so much easier - I wouldn't be without it. Mind you, I don't care particularly what things look like, just how they perform. Gordon.

That sounds right, Eugene. The hex is probably 1/4 British Standard in reality, which is pretty close to 7/16 AF. No real problems here with assuming spanner sizes to be British, since that is what we use most. Not many "American Freds" round here except Commando cycle parts!

Colin.

Previously wrote:

I use a worn 7/16" spanner (box end), cut short so it clears, I personally dont like the long BSA nut (bolt), looks odd to me. To clarify the wrench size,that'sactual7/16", in other words, 7/16" across the flats, NOT 7/16 Whitworth. It fits nicely in the tool roll since it is so small. Anna also mentioned a 7/16" wrench (she never said Whitworth).

Skip Brolund

I hear you Gordon, I just don't seem to have much trouble with the stock mag nuts with the right tool. Certainly not the worst nut on aNortonto get to. I guess it depends on the bike too, is it a dead original bike, or a modified bike. Kinda like timing cover screws, allen heads are better than slotted, but the slotted have an original look. Personal preference I guess. As long as it keeps another Norton on the road, its all good with me !!!

Skip

Glad you got it sorted Mike. Correct nut, if you are not going for the long B.S.A. bolt, is 1/4 B.S.F. (exactly the same, across the flats, as 3/16 whitworth, but finer thread). All the best, John.

gonna try and make a cranked spanner to get at nut

Previously wrote:

'Tis a pig to remove! I ground the sides on an open ended spanner, and was able to undo the nut one flat at a time. There may originally have been a special spanner made for this job, but, I guess you will have to adapt your own. You have my sympathy! i John

Glad I found this thread, I'm just about to start trying to remove my mag without having to dismantle the rest of the engine (Atlas) first.

Cheers all, John.

iI fitted a BSA A10 extended magneto nut a long time ago. It's a big improvement. My bike is very original, this is a 'rider' mod which is inconspicuous. If you decide to fit one of these special nuts, lay it across the engine plates where the magneo will be fitted, then insert the mag, fit the nuts (be sure to use the reduced-head nuts). It is very difficult / impossible to insert the extended nut after mounting the magneto

Paul

Previously Gordon Johnston wrote:

Available from any pre-unit BSA spares stockist. Gordon.

Previously mike_chizlett wrote:

Evening all,

I'm finding it very difficult to access and remove the lower nut closest to the crankcase thats attaching the magneto. Is there a special tool or some black art I should be aware of necessary to overcome this situation?

I have fitted commando primary cases which has meant locating the gearbox closer to the engine which hasn't helped the situation.

Even so, with the gearbox removed I still can't seem to get my spanner on the nut and turn it to a point where the spanner will come off with the nut in a different place.

Any suggestions greatly received.

I made a triangular nut out of some scrap steel. It just jams against the mag. No need for a wrench, just turn the bolt from inside the timing cover. To install the mag, hold nut in place with a long rod or screwdriver and wind the bolt in.

Even if you want to use the original nut, you don't need to turn it. Just hold it from turning and undo the bolt.

But of course we are talking about studs that locate and hold the magneto. If you are doing up a bolt from inside the timing cover, someone has removed the original stud and drilled through the case. Something I have come across before.

Gordon - good morning. When they moved to the twin coil system on 650s and Atlass they replaced the bottom waisted stud which was 5/16 inch Whitworth into the crankcase and 5/16 inch Cycle for the nut. The nut was a reduced hex down to a 1/4 BSF size. In the new arrangement a waisted bolt enters the timing-side crankcase with a washer and fibre washer to seal and a 1/4 inch Cycle nut with a thick washer secures the bottom of the points casing. The top two fixings remained as 5/16 inch studs. For the earlier bikes with magnetos I have always used a 3/16 Whitworth, double-ended, cranked, 50 deg, ring spanner ground down substantially and then cut in half to remove the part that gets in the way. All my friends and peers always had such useful items squirrelled away just for this purpose. The odd thing was that Norton did not list such a tool as necessary.....Ho hum ! Cheers, Howard

Aha! So that particular arrangement would only arise if you were to substitute a magneto instead off coil and points. A sensible move of course.

Previously Gordon Johnston wrote:

Aha! So that particular arrangement would only arise if you were to substitute a magneto instead off coil and points. A sensible move of course.

Hello Gordon,

Just to further all your options I have a few for sale, NOS Magneto replacement kits with Lucas RITA. Obviously such items really need alternator 12V electrics but they can be used with consideration with a dynamo.

AL Osborn