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Re: magneto removal dominator 88 [Re: ] #454417
09/15/12 6:47 am
09/15/12 6:47 am
Joined: Aug 2001
Posts: 7,549
scotland
triton thrasher Offline
BritBike Forum member
triton thrasher  Offline
BritBike Forum member

Joined: Aug 2001
Posts: 7,549
scotland
Originally Posted By: overandout
You guys should get outside more. Do any of you actually ride bikes or just invent problems to never be solved.I've had one magneto rewound in my whole life and the rest of them working for fifty years or so with original magnetism and original caps!


If specialist repairers spent their time "actually riding bikes," when would the repairs get done?

If you've been riding for fity years and only seen one erratic magneto, you've led a lonely sheltered life.


Amateur Loctite enthusiast.
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Re: magneto removal dominator 88 [Re: ] #454523
09/16/12 1:20 am
09/16/12 1:20 am
Joined: Aug 2001
Posts: 2,215
Oztralia
R
Rohan Offline
BritBike Forum member
Rohan  Offline
BritBike Forum member
R

Joined: Aug 2001
Posts: 2,215
Oztralia
Originally Posted By: overandout
What's lonely and sheltered about having reliable magnetos? If one fails in the future, big deal, just get another one.


The handbook for my old dommie lists getting the magneto serviced - yearly. Obviously Lucas did not consider them a fit-and-forget item ? Particularly lubing the bearings.

And given most maggies were not even built as fully waterproof, a decent thunderstorm or series of foggy mornings can see them need to be stripped and dried out...

You must belong to the same 'ride them and wreck them' school as a PO of my dommie - it came with 7ish 'spare' K2F's.
Close examination revealed all 7 unserviceable - cracked and broken castings, cracked and flogged out bearing housings and bearings, bent, broken and cracked armatures, pickups, shafts etc.

Maybe Lucas listed that yearly service for a reason ??
Back then, bikes were often ridden every day though, not playthings / Sunday rides like they often are today...

Re: magneto removal dominator 88 [Re: ] #454552
09/16/12 9:41 am
09/16/12 9:41 am
Joined: Aug 2001
Posts: 7,549
scotland
triton thrasher Offline
BritBike Forum member
triton thrasher  Offline
BritBike Forum member

Joined: Aug 2001
Posts: 7,549
scotland
Originally Posted By: overandout
What's lonely and sheltered about having reliable magnetos? If one fails in the future, big deal, just get another one.


My fault for crediting you with perception.

If you have only seen one failed magneto in fifty years, you have not used one much and you have not kept company with those who do.

When one fails, you "just get another one" from a specialist repairer. Someone like those two, whom you were taunting about getting outside more.

Last edited by triton thrasher; 09/16/12 9:41 am.

Amateur Loctite enthusiast.
Re: magneto removal dominator 88 [Re: Magnetoman] #454565
09/16/12 11:50 am
09/16/12 11:50 am
Joined: Mar 2012
Posts: 56
Outside Eastleigh, Hants, UK
K
Ken Tee, R.I.P. Offline
In Remembrance
Ken Tee, R.I.P.  Offline
In Remembrance
K

Joined: Mar 2012
Posts: 56
Outside Eastleigh, Hants, UK
Glad to see that this debate between Magnetoman and myself hasn't bored you all to death and that some of you are still here. He says he's not going to address any more of our experimental data. Oh well.

I have done some more experiments. Rigging up the power supply of our external magnetiser (which we don't normally use) in a different (and more dangerous) fashion shows that it was saturating the magnet of a K2F, but only just. I know that our internal magnetiser saturates the magnet ... vastly increasing the energy dumped into its coil above the amount normally used does not increase the magnet strength that is achieved, showing that it is saturating something. Drilling out 50% of the core of our internal remagnetiser (as I did with an earlier version of it) did not reduce the achievable magnet strength, showing that it was the magneto that was being saturated, and not the internal magnetiser's core.

In this morning's experiment, I magnetised a K2F using our internal remagnetiser, but in order to prevent the magneto being left keeper-less while I replaced the magnetiser's core with the magneto's armature, I placed the magneto in the frame of our external magnetiser while I did the swap, the external magnetiser's frame acting as a very good keeper. Whether I gave the internal magnetiser a full blast of energy, or only one third of it, the initial magnet strength (measured by the method previously described) was the same (and the same as for the external magnetiser).

But the important point is that, after the magneto had then been run as a magneto for a while, the magnet strength dropped to the same level, regardless of whether using the external magnetiser, the internal magnetiser, or the combination of the two as in this morning's experiment.

That is the point that Magnetoman's textbook quotes do not address. That is the point that Magnetoman has failed to address, other than his silly hole-picking in our experimental methods.

Ken
Brightspark Magnetos

Re: magneto removal dominator 88 [Re: ] #454566
09/16/12 11:56 am
09/16/12 11:56 am
Joined: Mar 2012
Posts: 56
Outside Eastleigh, Hants, UK
K
Ken Tee, R.I.P. Offline
In Remembrance
Ken Tee, R.I.P.  Offline
In Remembrance
K

Joined: Mar 2012
Posts: 56
Outside Eastleigh, Hants, UK
Originally Posted By: overandout
You guys should get outside more. Do any of you actually ride bikes or just invent problems to never be solved.I've had one magneto rewound in my whole life and the rest of them working for fifty years or so with original magnetism and original caps!

And what if I were severely disabled, unable to ride a bike, and eking out a living repairing mags so that there was one for you when your current one fails?
But luckily, between the two of us at Brightspark, we manage to clock up about 20,000 miles a year.
Ken.

Re: magneto removal dominator 88 [Re: Ken Tee, R.I.P.] #454575
09/16/12 2:00 pm
09/16/12 2:00 pm
Joined: Nov 2011
Posts: 4,642
U.S.
Magnetoman Offline

BritBike Forum member
Magnetoman  Offline

BritBike Forum member

Joined: Nov 2011
Posts: 4,642
U.S.
Originally Posted By: Ken Tee
He says he's not going to address any more of our experimental data. Oh well.

I have done some more experiments. Rigging up the power supply of our external magnetiser (which we don't normally use) in a different (and more dangerous) fashion shows that it was saturating the magnet of a K2F, but only just.
To measure the B-H loop of an isolated piece of alnico in order to know a particular electromagnet is capable of saturating it is hardly straightforward even with a well equipped lab, and to do it when that alnico is embedded in a complex magnetic circuit much more so. Since your results are inconsistent with my own data on fully-saturated magnetos, and are inconsistent with what is written in books, I have good reason to believe you have made a mistake in the measurements you say you have made.

In answer to my question about whether your external electromagnet had sufficient strength, in your previous post you wrote: "I doubt very much that it did, but I don't see the relevance of that." However, after I explained to you why it was very relevant to whether or not your internal magnetizer functioned as you claim it does, you now find that your electromagnet was just fine after all. The reason I'm not going to address your experimental data is it would require me asking for a lot of details to understand why you think you were able to accomplish what you say you accomplished, i.e. experimentally determine your external electromagnet actually has saturated the alnico in the magneto, when two days ago you "doubt[ed] very much that it did."

Originally Posted By: Ken Tee
That is the point that Magnetoman's textbook quotes do not address. That is the point that Magnetoman has failed to address, other than his silly hole-picking in our experimental methods.
For you to (incorrectly) say those textbooks don't address the effect of actual operation of a magneto on the strength of the alnico means you have managed to get ahold of those books and read them over the past two days. If so, the interlibrary loan system in England is remarkably efficient, since in the U.S. it would take at least a week (and, more typically, up to a month) for the local librarian to track down those books and get them shipped in. Be that as it may, you really do need to re-read those books for the important information you missed. Just the fact each of them goes to lengths to emphasize the importance of magnetizing the magneto as a complete assembly, and describe the consequences of not doing so, should tell you that it is unlikely that two pages later they say doing so is irrelevant for the actual operation.

I've responded politely to each of your posts with relevant information about experimental mistakes you made, incorrect inferences you drew from a badly conceived experiment, and references to texts that contradict your methods. I have done this despite your continuing sarcasm and insults. However, at this point it comes down to your claims that your experimental methods are fine, and that over the past couple of days you have managed to find and read the books I referenced and they have nothing relevant to say about the behavior of magnetos in actual operation.

People can follow my ongoing restoration of a magneto in the Members' Bike Projects forum to judge my own technical competence on the subject of magnetos. But, it's hard to imagine continuing this 'magneto removal dominator 88 thread' without issuing insults of my own, so this will be my last post here.

Re: magneto removal dominator 88 [Re: strenny] #454617
09/16/12 8:23 pm
09/16/12 8:23 pm
Joined: Jan 2008
Posts: 329
Concord Township, Ohio
57nortonmodel77 Offline
BritBike Forum member
57nortonmodel77  Offline
BritBike Forum member

Joined: Jan 2008
Posts: 329
Concord Township, Ohio
Well, since I am not a scientist, or a professor, I suppose my simple methods & observations may not be relevant to one person here, but as I see it I have personally re-magnetized a small number of mags with a simple vintage 12 volt dc Bosch magneto re-charger & absolutely no extra effort is required to start it, 2 of the Lucas mag/dyno's I have done are owned by 70-80 year old men who cant believe how easy their (Norton inter.& BSA Goldstar) both start, in fairness, I also installed the Brightspark Easycaps instead of the sill old fashioned epoxied in capacitors buried in the bowels of the armature (but that's another story for another thread). Out of respect for magneto mans day job at the University I dont doubt that perhaps some of his magnetic theories are correct in a lab,on paper, or perhaps in reality, buy lets face it the average vintage bike guy with a mag, just want his bike to start & start easy. Even "if" the science showed one ten thousandth of a percent better magnetism with magmans method, in the end, the bikes owner doesn't care, as long as his bike starts easily. I recently got a mag recharged by a very reputable mag-man in Pennsylvania, I sent him my empty mag housing without the armature & he recharged it w/o a keeper & sent it back to me, & it works a treat! I think science is great, but sometimes it causes overkill with engineers & scientists.

As to Ken at Brightspark, I have never met him personally, & have never been at his shop, but I do know a number of people who have had him rebuild their mags & everyone of them can't say enough about his professionalism & high quality work. I also know that his reputation is stellar & unblemished. Considering how may mags he has done & how many easycaps he has in use around the world, he must be doing something right. In these times of easy internet access, if you screw up, the world knows about it in no time!

Lots of data on this thread, it was a good run, but in all fairness, 90% of this thread was off topic, perhaps at a later date we can pick up where this thread left off on a new thread.

All the best,

Skip Brolund


Magneto & Dynamo restorations & supplies

My Bikes
1948 Norton 500T Trials bike
1950 Norton Model 7
1952 Norton ES2
1957 Norton Model 77
1960 Norton Nomad 600cc Desert sled
1961 Norton ES2 (slimline)
1964 Norton Atlas Scrambler
1972 Bultaco Alpina
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