The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: 427Thunderbolt on 10.06. 2016 20:12
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Like an idiot , I purchased a new Mag without doing any research since it said Lucas mag replacement in the description . so the story goes .... I ordered a Morris but received a Hunt by mistake . I carefully tried to hold the Hunt up to the mounting location on the rear timing plate and it touches the crankcase/cylinder jug area long before it is positioned straight . The Morris should be arriving next week but I think it is identical to the Hunt as far as the outer dimensions go. Has anyone made one of these work with an a10 preunit ? It looks like if they just made the removable mounting pad on the bottom of the mag at the right clocking it would fit ? Anyways it is looking like I will be sending my original mag off for a rebuild . Who should I send it to?
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I had to google Morris magneto as I'd never heard of them, is this below the mag you bought?
http://shop.morrismagneto.com/t/triumph-/-yam-xs-650
It looks like ithe Morris TPL model might be equivalent to the Lucas K2F mag fitted to a10's as oem? but from what you are saying it fouls the crankcase? If it could be made to fit I think there might be a few people who would be interested in finding out about them.
I think hunt of the U.S. make a mag that bolts on in place of the standard mag, Rocket Racer on this forum runs these on his sidecar racer.
I use a fully electronic mag from BTH see:
http://www.bt-h.biz/k2f--lucas-replica-flange-magneto-13-p.asp
Sorry but I cannot recommend a oem mag restorer but I think you may be able to get a replacement armature/coil from Draganfly in the u.k. But I've no experience of buying one from them.
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The Lucas K2F for our BSA A7/10's has a flat section ground off the case to clear the engine case. So a K2F off a Trihard won't fit.
You might find the Morris is the same as the Hunt if it's not specifically made for a BSA. Close your eyes and *work* (maybe not close your eyes).
Cheers
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It is strange that anyone supplying a replacement for the K2F should make no allowance for pre-unit BSA twins. Those bikes may actually be the commonest K2F fitment.
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When I was in Dallas, TX last year I stopped in to visit at Stovall's Cycle. They had several mags they had rebuilt. Phone number is 214-398-6500
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Actually, point of order here! An unchamfered K2F will fit on one of our beasts - or at least it will on swing-arm ones. I've run with unchamfered K2Fs, and K2FCs, as well as the chamfered one that (I think) is on it at the moment.
But I don't know how tight things are on plunger models, what with there being less space to play with.
It is also worth noting that a lot of the early ones have the smaller 15mm drive end shaft diameter, which some people regard as a point of weakness compared with the 18mm jobs which came in from about late '51.
There are loads of K2Fs with the chamfer on them though, because as TT says, there were gazillions made.
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On the topic of getting a mag rewound, I spoke to a well respected mag restorer in NZ (now retired) about the process and it became clear that, to get the cost down (and quality up) to a reasonable level, batches of 50 or preferably 100 had to be done at a time, due to winding and curing machine set up time etc. Which meant he had to buy old mags up of the various in some quantity before being to offer a restoration service on a particular mag type. Obviously if you were prepared to pay $$$$$ you could get one offs done (he could make vintage aircraft mags pretty much from scratch).
Depending on what sort of manufacturing machines other restorers have, the same might apply, the cost might be quite high (and quality unknown?) unless the restorer is well set up to restore KTFs, it certainly is worth asking the right questions anyway.
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That doesn't really stack up KiwiGF. Coils are wound one by one (to the known spec in terms of gauge of wire, number of turns etc for all the common ones, some detective work required to figure out the 'recipe' for rarer things sometimes), and it isn't a big deal to go from, say, a K2F to a Magdyno MO1 or a BTH or whatever. All the decent trade winders out there operate much the same way. There are some differences in equipment used, as there are quite tasty CAD machines available these days, which speed things up, but it still comes down to a job by job approach for that side of it.
For the lotions and potions used to impregnate and cure the coils, yes, batches are normally done together - but '50 or 100' implies a factory-scale operation, whereas most of those who do this stuff are more in the cottage industry category.
One-offs are done all the time and every day - whether it be a pre WW1 Splitdorf, a Simms from a vintage commercial vehicle, or a tiddler from a small '20s 2-stroke (just to mention a few that have come through here lately and for which there was no problem in getting them rewound at reasonable prices).
The quality is a factor of who does the wind frankly. The old apprenticeships for winders were 5 years, by the end of which someone would be experienced in anything from large industrial motors and generators, down to the human-hair scale windings of HT coils for magnetos.
Considering the delicacy of the job, it is a tribute to all those who do the winding that the failure rate on rewound coils is pretty low. But as with all things, shit happens now and again, as often as not due to variable wire quality or insulating material problems. I and my Brightspark mate the late KenF must by now have fed way over 1000 HT coils through the channels we use for rewinding (neither of us was going to start self-apprenticing in late middle-age when there are fully-skilled people out there!) and of that number, there has been a tiny handful of failures, always rectified immediately by the coil winders. A K2F or MO1 is a standard job for most of these people, and they do them quickly and well, so we shouldn't have any great problems in sourcing good quality refurbishments for as long as these folk keep going.
That said, there are rather less good efforts out there too, which don't pass the basic coil tests imposed by Lucas (as found in their workshop instructions). Comes back to 'who does the job'.
This does lead to the question of 'what next'? Most people doing this stuff are not young (60+ is common). Most people's offspring can think of less tricky ways to earn a crust. Beezermac spoke recently and very eloquently of the difficulty of getting a work/life balance, and it's the same problem for a lot of people. In another few years we shall have to have fresh solutions to the problem unless new blood comes into the arena. We've had 20 or 30 years of relative comfort, which followed the difficult period where NOS Lucas parts became thin on the ground and there weren't many folk offering rebuild services. That era is coming to an end.
One interesting discussion in which I am engaged is for the possible manufacture of brand new armatures, with new CNC-machined end cheeks, with new laminates and coils: ie, NEW, so no oversized air-gaps due to several-times-machined parts, no bent drive ends, no damaged tapers, no messed up threads and mismatched parts. But these are not trivial things to do, requiring investment and time. And it also has to be looked at in the context of some of the competing ignition options that are becoming popular. While we who want to stick with 'proper' magnetos are all still able to recycle only faintly-mullered parts to keep going, the need may not be desperate - but the day will come. Many BSA owners complain that their ATDs turn out-of-true on the end of bent shafts, that the ATD or pinion doesn't fit where it should on the taper, etc. The idea of having completely new bits available is appealing. So is the parallel idea of making brand new brass-type contact breaker backplates of a better quality than the steel-backed type that is currently available. Again, it's a question of time and money and the waning availability of serviceable bits. We're a notoriously tight-wad group of people sometimes, thinking often it terms of what a factory price-list from the '50s looked like. When Lucas was brow-beaten to supply whole magnetos for not much more than a pound. BTH refused - and although they made good mags, how many KC1/2s are there compared to Lucas K1/2Fs? Norralot.
I've strayed off the initial topic here a bit, but the main point is that 'any job can be done, and done properly' and should be affordable while the skills last. When the skills have, literally, died away or retired, what then? Electronic options are luckily there, but we need also to be thinking about revitalising the core competence of maintaining and mending magnetos, and ensuring that parts remain available, if people want to continue with what the makers intended.
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That doesn't really stack up KiwiGF. Coils are wound one by one (to the known spec in terms of gauge of wire, number of turns etc for all the common ones, some detective work required to figure out the 'recipe' for rarer things sometimes), and it isn't a big deal to go from, say, a K2F to a Magdyno MO1 or a BTH or whatever. All the decent trade winders out there operate much the same way. There are some differences in equipment used, as there are quite tasty CAD machines available these days, which speed things up, but it still comes down to a job by job approach for that side of it.
For the lotions and potions used to impregnate and cure the coils, yes, batches are normally done together - but '50 or 100' implies a factory-scale operation, whereas most of those who do this stuff are more in the cottage industry category.
One-offs are done all the time and every day - whether it be a pre WW1 Splitdorf, a Simms from a vintage commercial vehicle, or a tiddler from a small '20s 2-stroke (just to mention a few that have come through here lately and for which there was no problem in getting them rewound at reasonable prices).
The quality is a factor of who does the wind frankly. The old apprenticeships for winders were 5 years, by the end of which someone would be experienced in anything from large industrial motors and generators, down to the human-hair scale windings of HT coils for magnetos.
Considering the delicacy of the job, it is a tribute to all those who do the winding that the failure rate on rewound coils is pretty low. But as with all things, shit happens now and again, as often as not due to variable wire quality or insulating material problems. I and my Brightspark mate the late KenF must by now have fed way over 1000 HT coils through the channels we use for rewinding (neither of us was going to start self-apprenticing in late middle-age when there are fully-skilled people out there!) and of that number, there has been a tiny handful of failures, always rectified immediately by the coil winders. A K2F or MO1 is a standard job for most of these people, and they do them quickly and well, so we shouldn't have any great problems in sourcing good quality refurbishments for as long as these folk keep going.
That said, there are rather less good efforts out there too, which don't pass the basic coil tests imposed by Lucas (as found in their workshop instructions). Comes back to 'who does the job'.
This does lead to the question of 'what next'? Most people doing this stuff are not young (60+ is common). Most people's offspring can think of less tricky ways to earn a crust. Beezermac spoke recently and very eloquently of the difficulty of getting a work/life balance, and it's the same problem for a lot of people. In another few years we shall have to have fresh solutions to the problem unless new blood comes into the arena. We've had 20 or 30 years of relative comfort, which followed the difficult period where NOS Lucas parts became thin on the ground and there weren't many folk offering rebuild services. That era is coming to an end.
One interesting discussion in which I am engaged is for the possible manufacture of brand new armatures, with new CNC-machined end cheeks, with new laminates and coils: ie, NEW, so no oversized air-gaps due to several-times-machined parts, no bent drive ends, no damaged tapers, no messed up threads and mismatched parts. But these are not trivial things to do, requiring investment and time. And it also has to be looked at in the context of some of the competing ignition options that are becoming popular. While we who want to stick with 'proper' magnetos are all still able to recycle only faintly-mullered parts to keep going, the need may not be desperate - but the day will come. Many BSA owners complain that their ATDs turn out-of-true on the end of bent shafts, that the ATD or pinion doesn't fit where it should on the taper, etc. The idea of having completely new bits available is appealing. So is the parallel idea of making brand new brass-type contact breaker backplates of a better quality than the steel-backed type that is currently available. Again, it's a question of time and money and the waning availability of serviceable bits. We're a notoriously tight-wad group of people sometimes, thinking often it terms of what a factory price-list from the '50s looked like. When Lucas was brow-beaten to supply whole magnetos for not much more than a pound. BTH refused - and although they made good mags, how many KC1/2s are there compared to Lucas K1/2Fs? Norralot.
I've strayed off the initial topic here a bit, but the main point is that 'any job can be done, and done properly' and should be affordable while the skills last. When the skills have, literally, died away or retired, what then? Electronic options are luckily there, but we need also to be thinking about revitalising the core competence of maintaining and mending magnetos, and ensuring that parts remain available, if people want to continue with what the makers intended.
This post is very good; I think it should be published in the BSAOC magazine so that more people can see it. Would you mind if I forwarded it to the editor?
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Only one man's view Greybeard (hope it's not too one-eyed) but quite happy for you to use/abuse/amend as you like. Have sent you a PM. Cheers,
Bill
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That Groily is a wise man, but don't tell him I said so.
Richard L.
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Won't say a word Richard, I promise. I'd hate to spread untruths.
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I run a Joe Hunt on Bender (my 55 road rocket).
To get it to fit properly we replaced the flange with a thinner one as the taper wasn't in the right place.
We also milled the back of the crank cases to provide more clearance having tried initially to file the bakerlite cover where it fouled.
It now has grooved mounting bolts so timing can be adjusted by rotating it.
I initially had several faulty coils, but the current one has been reliable for a number of years now.
So it wasnt a simple exercise but having gone through some pain I now have a mag up to the task of burning methanol effectively with a big fat spark *wink2*
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You're probably well-advised to have done that RR!
However, some of the older units can withstand the pressure too, but I don't know for how long.
A recent job involved a BTH TT model supporting a methanol burning J A P engine running 14 or more : 1 for a 4-wheeled hill climb special . . . the first new coil didn't make it after a few ascents of one of the well-known UK hills, but a second one is (I think) doing well. I await news on a K2F which is being expected to propel a methanol burning modded RE twin sprinter - I have expressed some doubts and held back on offering generous warranties!
The Technical Officer of one of the vintage car clubs in the UK is of the view that rotating coil mags won't thrive at speeds of 6000rpm+ at the magneto and I can't disagree. On a typical 4 cyl engine such a mag will be running at engine speed - so is working very hard indeed. For us, at least, the thing is running at half speed.
In these cases there is a lot to be said for more modern upgrades using fixed coil mags like RR's or a total loss electronic system using a small battery concealed somewhere, as the compression ratios involved demand a pretty high secondary voltage to spark.
As a rule of thumb, roughly, a spark gap of 0.8mm in plain air needs 1000v to make the leap.
An 18- 20 thou spark gap on a plug, at a lowly comp ratio of 5.5:1 requires about 7000 volts in cold air (less at the several hundred C° you find in a running engine though). Lucas recommended conducting all tests using 5.5 mm three point gaps for slow speed testing, implying that same voltage of around 7000 (with the use of 'utility factors' - variable resistance - to replicate the effect of grotty running conditions if required).
When you get to 12 or 14:1 compression ratio, the voltage required will be right up there, with consequent stress on the HT coil's insulation, and on the slipring and other plastic bits. And very high rpm don't help a rotating coil, with the forces it is subjected to. If running on methanol - which I think runs cooler than normal juice? - the benefit of high temperature in reducing the sparking voltage reduces too. A demanding combination.
So horses for courses I reckon, even if a traditional mag will often do the job.
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Bill,
I have heard good reports on the old BTH mags. At the time I bought the Joe Hunt, I was happy to get something new and off the shelf. It still gave me some headaches though.
We do have limited magneto reconditioning options down here compared to the UK. Before I had bought mine, a good mate had fitted a locally reconditioned competition lucas to his methanol racing vincent. It failed and the result was a broken crank. He then fitted a Joe Hunt.
The catch with old mags is its not just an electrical component but a mechanical one too and few in our neck of the woods are competent in both areas.
Going back a few more years I had a vintage club colleague who had a mag done in Wellington (the reconditioner who was well known has since retired) , it sparked beautifully but was unreliable as it hadn't been given sufficient mechanical bearing clearance (wasn't shimmed properly if at all). I shipped the guy just my armature only and once I'd reassembled it ran happily for around 15 years on my humble B33
With a good reconditioner standing behind the product I would be happy to run a BTH or Lucas K2F ( I have one in need of attention as a spare) but we lack that here *cry* . I've seen some UK suppliers have stopped accepting overseas work due to excessive demand.
I did also buy a modern BT-H before the Joe Hunt, but it had a modern short duration spark and wasnt very satisfactory with Methanol, so its spare to go on my road based Super Rocket (still a work in progress)
Tim
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You could send it to Australia, RR. There's quite a few good repairers here.
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You could send it to Australia, RR. There's quite a few good repairers here.
Sorting the manual advance K2f mag isnt high on the list as I've got a BT-H that should get "Rusty" my super rocket mobile, but if you can recommend someone good on the east coast of the big west island of Noo Ziland, would be good to know...
I couldn't currently recommend anyone in the NZ north island. *dunno*
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I had my K2F rebuilt by Peter Scott about 30 years ago. It worked faultlessly for about 15 years (I then went electronic). It still gives a good spark when spun by hand. http://dropbears.com/motorcycles/peter-scott/
Zochy's is another. I haven't tried. Funny their both in seven Hills Sydney. http://www.zochys-magnetos.com/
Cheers