Author Topic: strange goop in magneto - what is it?  (Read 1672 times)

Online groily

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Re: strange goop in magneto - what is it?
« Reply #15 on: 04.05. 2016 17:21 »
Happy to chime Richard, but have been looking at the pic and not knowing what to think!

First thought was goop used to embed a modern condenser, but I couldn't figure the threads or thin filaments in the muck, and then the condenser in a K2F is the opposite end from the condenser, and said goop is unlikely to swap ends if it self-detaches. There isn't much room to go walkabout..

Then I also thought some sort of silicon sealing goop applied round the plug leads/acorn nuts to keep fuel and water out. It doesn't really look like slipring material from what I can see, but you never know. There are white sliprings, but the form and shape of the goop looks odd to me, and as you say, the slipring would look emaciated through the pick-up holes if that much had been carved off it. Sometimes, if a brush has self-detached the bits can do some carving, and the spring, if it's still there, can make a bit of a dog's dinner of things. Been there and had that with one of mine not so long ago. Still ran (badly), but the slipring plastic was scored to a depth of about 1/8th of an inch and the step between brass and plastic was huge.

Could be some sort of resinous coating that has peeled off the armature windings I suppose, for not being heat-resistant enough, or not able to expand with heat. One does see some coils that look like a resin egg, solid as a rock and shiny/smooth all over, but would they or could they shed bits like this? I don't know.

Unless I could identify it for sure, and found it was definitely harmlesss and not capable of happening again, I think I would open the mag to see whether there was anything bad starting to happen though.

Not much help I fear - but will be fascinated to learn in due course, if an answer comes out in the wash that is.
Bill

Online bsa-bill

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Re: strange goop in magneto - what is it?
« Reply #16 on: 04.05. 2016 19:57 »
final throw of the dice - ectoplasm
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline a10gf

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Re: strange goop in magneto - what is it?
« Reply #17 on: 04.05. 2016 20:35 »
^^^ lol. Apart from ghosts trying to manifest inside the mag, it has to be lacquer\shellac from the external layer of the armature ??

A10 GF '53 My A10 website
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Online mikeb

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Re: strange goop in magneto - what is it?
« Reply #18 on: 08.05. 2016 08:12 »
I'm posting back some more info on this problem, now resolved (I think), as from comments above its looks like I've stumbled upon some unusual weirdness.

re the shellac theory, I let those flakes sit in meths overnight and they're not dissolved. so probably not shellac. tho I guess its possible the windings could have been replaced in the maggie and it's some modern compound of similar function.

Richard asked the question of if the slip ring looks scoured. quite tricky to get a good look in there without taking the maggie off (and I keen not to as I'm readying the bike for a rally next weekend). even harder to get a good photo. but have a look at the two photos below - they look scraped and scoured  to me.... is that normal?
I've done 90 miles on the bike since changing to the new 'new lucas' brushes (and new-new pickups) and when checked today have no more goop. So at this stage I'm going to conclude it was most likely the 'new' brushes (on the new taiwanese hex pickups) with the sharp square profile scouring the slip ring material.

I ?think? its the most plausible explanation ??? (ghosts, hexes and spiders aside).
on the bright side, at least those brushes where hard.
on the practical side, if I ever get brushes like that again I'll chamfer the contact surface before installing.

Thanks for your comments everyone
New Zealand
'61 Super Rocket  - '47 B33 -  '18 Triumph Street Triple RS

Online bsa-bill

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Re: strange goop in magneto - what is it?
« Reply #19 on: 08.05. 2016 08:57 »
well well,looks like you were on the ball from the start, well done.
Now I have never seen a slip ring made of what looks like white stuff, is this a gap in my A knowledge or is this a rare breed of Lucas component stock 
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Online RichardL

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Re: strange goop in magneto - what is it?
« Reply #20 on: 08.05. 2016 13:26 »
It looks trashed to me. As always, other opinions are a good thing.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Offline a10gf

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Re: strange goop in magneto - what is it?
« Reply #21 on: 08.05. 2016 14:36 »
That was unexpected. A white plastic slipring!? Or some soft nylon? But obviously not coping with normal use. Thanks for posting the findings, may stop others from buying any of those. Fit a new one, from a reputable source.

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Online RichardL

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Re: strange goop in magneto - what is it?
« Reply #22 on: 08.05. 2016 14:52 »
We might have a winner (loser?). https://www.rabers.com/item.asp?pno=455361

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Online groily

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Re: strange goop in magneto - what is it?
« Reply #23 on: 09.05. 2016 17:06 »
How much Richard??? Bleedin' 'eck - $118 is a lot in any currency!

There are a white sliprings out there, but I don't see them on Lucas mags - rather on Bosch and some other 'Continentals'.
And there are new white ones being made for some makes (I have a few). However, there are excellent black Lucas anti-clock- and clockwise sliprings for around 28€ (etc, etc in other money) which are what most repairers use and most individual owners buy if tackling stuff themselves - and which certainly shouldn't be eaten like that. They aren't bakelite, being a teflon/nylon type compound which is not brittle, but which wears very well.

Certainly seems as if that one has been well carved up. In that state it might well eat a new set of new brushes in short order and make things worse. So I don't think crossing fingers or touching wood is a safe option, to be really honest.
Bill

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Re: strange goop in magneto - what is it?
« Reply #24 on: 09.05. 2016 17:59 »
The more I look at it the more the one from Raber's looks like really old discolored (oxidized?) Bakelite which might have been black at one time.

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Online chaterlea25

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Re: strange goop in magneto - what is it?
« Reply #25 on: 09.05. 2016 21:22 »
HI All,
Richard,
The Rabers slip ring looks like an original Lucas with the moulded in part number
I had a NOS one and it was that kinda "coffee" colour, It didnt last long with some or other pattern brushes  *sad2*

The goop is I believe half melted shards of plastic/nylon from the gouged slipring ????
It could be a "homemade" lump???
As Bill mentioned there are "white" sliprings out there, I was told that these come as a kit and can be assembled to the required setup? These are supplied by "TheDole" magneto guy in Holland as far as I know

John
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1963 RGS (ongoing)

Online groily

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Re: strange goop in magneto - what is it?
« Reply #26 on: 10.05. 2016 06:56 »
Exactly as John says. Many original bakelite ones were coffee coloured with, in many cases, the part number stamped on.
Theodole does indeed sell kit-form white ones. The ones I have from him are designed for Bosch primarily, and come as 3 or 4 parts - two flanged sides, and either a 360° brass ring for singles or mags with distributor heads, or a matching brass segment and a nylon segment which can be clicked in like Lego to get the brass in the right place for either rotation, for parallel or V twins. These would probably go on most BTH mags (but no need, as sliprings specifically for all BTH are easily available, as for Lucas), but the diameter is small for Lucas. Other white jobs turn up on some other mags, whether original or not I don't know. But haven't seen a white 'Lucas' one  . . . so far.
Bill

Online mikeb

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Re: strange goop in magneto - what is it?
« Reply #27 on: 10.05. 2016 08:58 »
this slipring is white and nylon / plasticy. not bakelite. i don't know its history.
ok so the consensus appears to be that this slipring is pretty damaged and likely to eat the new brushes and should be rpelaced. as i'm new to all this would anyone risk plotting the likely failure path of this thing? how do sliprings fail? and how long may the brushes last? are they likely to just wear fast or more break apart catastrophically against the rough surface?

thing is, i'm off to a 300+ mile rally this weekend and don't have time to attend to it before I go, and my alternative b33 has maimed electrics and a hot start problem. (and I really want to take the rebuilt a10  *smile*)
I do have yet more brushes I can take as spares for the rally.

(and does anyone else find their lives get in the way of time for bike maintenance?)
New Zealand
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Offline duTch

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Re: strange goop in magneto - what is it?
« Reply #28 on: 10.05. 2016 09:38 »

 Mike, if possible a pic of each end of the brass bit could maybe helpful to determine how much of a there step is-if any.
 
 I say you'll have black markings on any slipring, just they're not as noticeable as on a white one, but still can't suggest anything on the swarf (if that's what it is), unless there's interference with the little pointy watchamacallem little screws that sometimes apparently arc out and cause diferent trouble *dunno*.

 Regarding the brushes, if they mark the same dark marks on paper maybe they're the same grade. Maybe you can just sculpt them and shape the ends to suit?
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Online RichardL

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Re: strange goop in magneto - what is it?
« Reply #29 on: 10.05. 2016 12:42 »
...i'm off to a 300+ mile rally this weekend and don't have time to attend to it before I go, and my alternative b33 has maimed electrics and a hot start problem. (and I really want to take the rebuilt a10  *smile*)

I am hesitant to suggest you forego the fun of the rally, on the chance that you might actually make it. On the other hand, a 150-mile recovery will be pretty expensive. I am guessing no one here is going to say, "Go for it, everything's going to be fine." When you look at it does it give you a high level of confidence? Could you come up with a loaner mag for the trip? Could you get the armature to a lathe for a cleanup? Could you quickly get a new slipring from that dealer in Melbourne? (I think "in Melbourne". Can't recall the name right now, but known for being gruff).

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.