The BSA A7-A10 Forum

Technical => Lucas, Electrical, Ignition => Topic started by: michael snellin on 04.10. 2013 08:48

Title: K2f mag??
Post by: michael snellin on 04.10. 2013 08:48
Hi, can anybody explain the workings of the above magneto i know that it does generate its own current seperate from the other electrics i purchased a manual mag from a well known jumble and in working order but it is the direction that the mag runs in IE clockwise/anticlockwise ??that i am a bit lost and the auto/adv, i have the assembly for a auto/adv that came with the rest of the bit and pieces with another mag that does not work is there a difference between these components the AUTO/ADV timing piece? and can i use this with the manual mag?
                       appologies for not being to clear ?????
Title: Re: K2f mag??
Post by: bsa-bill on 04.10. 2013 10:34
A few good experts on this forum who are very helpful, I'm far from an expert but can answer a couple of your questions until more knowing members comment.

Rotation - this is as viewed from the driven end ( the end with  A/R unit on it) and if it's on an A7/10 it's anti clockwise and should be marked as such on the plate at the drive end.
be aware that for A7/10 s a bit of the shoulder of the body is relieved to accommodate the crankcase, compare the one you bought with your original.

The Auto advance unit can be used with a manual magneto if you lock it up so it can't move (weld?), but solid pinions are available and not too extremely costly (better option I reckon)

most common faults I think are breakdown of the insulation in the windings, and capacitor goes duff, both these are the cause of non starting when warm (will start ok cold), loss of magnetism (standing unused for years), dirty slip ring due to long use or more likely these days soft brushes in the pickups and now we here there are faulty pickups on the market as well.

and the points need to be kept clean and adjusted to correct gap.

all the best with it - Bill


Title: Re: K2f mag??
Post by: a10gf on 04.10. 2013 12:27
As Bill says. Here's a picture (A10 mag), see the arrow > counterclock seen from drive side (= clockwise seen from points side).
Title: Re: K2f mag??
Post by: Triton Thrasher on 04.10. 2013 19:23
When you buy any magneto, you might as well budget for a rewind.

You can use an auto advance and just leave the manual timing fully advanced.
Title: Understanding the Mag ????
Post by: michael snellin on 05.10. 2013 08:04
Hi,thanks to everyone for there input re: the above item ? it does appear that i may have the wrong mag ie: the rotation, i was just wondering if it is possible to change the rotation by altering the points. would anyone know???
                         These things happen when you get hold of a A10 frame and nothing else ! urgh!!


adm edit: topics merged
Title: Re: Understanding the Mag ????
Post by: bsa-bill on 05.10. 2013 08:54
I'm not sure if it makes any difference to the windings which way they turn , not sure about the wiring of the capacitor newer ones might be polarity sensitive, but rotation will matter to the cam ring and maybe the slip ring.
some new points are made so they do both rotations, but there again there are two types about these days brass plate and steel plate and you need a centre bolt to match.

You need ( and will probably get) advice from an expert here, but I'm not sure your best plan might be to find out what bike your maggie was intended for and consider selling or swapping.
Sparkier brains may comment  *smiley4*
Title: Re: Understanding the Mag ????
Post by: KenF on 05.10. 2013 13:46
Hi,thanks to everyone for there input re: the above item ? it does appear that i may have the wrong mag ie: the rotation, i was just wondering if it is possible to change the rotation by altering the points. would anyone know???
                         These things happen when you get hold of a A10 frame and nothing else ! urgh!!
If the K2F is in fact clockwise at the drive end, Michael, then to change it to anti-clockwise, you would need to:
There's no need to change the windings, condenser or polarity of the magnet.

But before doing any of that, are you really sure it is in fact currently a clockwise K2F. They're not very common. Some may have been retro fitted to Oilfield twins, and the racing version was standard on some Dougys.

If it's anti-clockwise, it will look like this:
(http://brightsparkmagnetos.com/images/C01%20and%20CB%20assembly_small.JPG) or this (http://brightsparkmagnetos.com/images/C04%20and%20CB%20assembly_small.JPG)

Early brass CB assembly on the left. Later steel CB assembly on the right. (Ignore the green EasyCap condensers thingies, and odd screw in the right hand pic.)

On the other hand, if clockwise, it'll be a mirror image.

So, are you sure it's clockwise?

Cheers,

Ken. http://www.brightsparkmagnetos.com (http://www.brightsparkmagnetos.com)
Title: K2f Magneto
Post by: michael snellin on 06.10. 2013 15:04
Hi,everyone iv,e checked my mag and it does run in a clockwise direction? thanks to all who helped me with this problem and thanks to to person who supplied the pics;i suppose as one member has said it may well want a rebuild and i will do this when the time is right Has any one fitted the electronic ign too there bike and if so what are the pros and cons.
                                            thanks.


adm edit: topics merged. No need to start a new topic for every reply.
Title: Re: K2f Magneto
Post by: Triton Thrasher on 06.10. 2013 16:30
A good magneto gives happier riding than electronic ignition powered by a Lucas dynamo.