Author Topic: strange goop in magneto - what is it?  (Read 1746 times)

Online WozzA

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Re: strange goop in magneto - what is it?
« Reply #30 on: 12.05. 2016 01:32 »
Quote...  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).    *eek*

Might that be Dave from MODAK?    *whistle*  :o     http://modakmotorcycles.com.au/   
'51 Golden Flash Plunger
'57 Golden Flash Swingarm

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Online RichardL

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Re: strange goop in magneto - what is it?
« Reply #31 on: 12.05. 2016 04:48 »
Hmmm. I had found Modak's name shortly after writing that and I thought I had revised it, leaving off "gruff".

If you are reading here Mr. Modak, no offense meant from a dumb American. Many here on the forum appreciate your help and services.

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.

Offline beezermacc

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Re: strange goop in magneto - what is it?
« Reply #32 on: 12.05. 2016 09:02 »
As you have replaced the brushes I would guess that the problem is now solved. I'd give the bike a run, maybe 30 miles or so and then remove one of the pickups and see if there is any noticeable change in condition. If everything looks OK stop worrying! After all, there's no point in having an old bike and not using it. In the UK we have breakdown insurance so the worst case scenario is we get driven home in pickup!

Regarding slip rings generally (sorry if this is repeating previous posts) I use the black plastic slip rings which seem to have superb anti-friction characteristics but also they're not brittle. The original Lucas slip rings can have hair-line cracks which are difficult to detect. I saw the white, self assembly ones, at Stafford a few years ago and thought they were a good idea but they were very expensive. It appears now, from this thread, that the material isn't as friction proof as the black ones.

Regarding brushes, the original Lucas brushes had a fine groove down their length and a very light spring. If anybody has brushes like this, provided they are serviceable, I would advise sticking with them. I've had no problems with the replacement brushes from Wassells except that the springs are a bit heavy and short so, when fitting, it is necessary to make sure they are contacting the slip ring properly. However, these brushes are not the same as the ones supplied with Wassells pickups. I find these brushes to be much too soft, i.e they fail the graffiti test!, so I always chuck them away and fit the better quality brushes which I know are OK because I use them in my own bikes. It's weird that Wassells supply complete pickups with cr4p brushes yet sell perfectly good brushes separately! When using the replacement brushes I always rub their tips on some ordinary paper before fitting to clear away any loose particles and remove roughness from the surface. After a bit of a polish they leave no marks at all. 
Priory Magnetos Ltd - A10 spares, magneto and dynamo refurbs. www.priorymagnetos.co.uk

Online RichardL

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Re: strange goop in magneto - what is it?
« Reply #33 on: 12.05. 2016 12:15 »
It will be very interesting/enlightening to hear the results of the test ride. Good advice from Andrew, of course.

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 bsa-bill

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Re: strange goop in magneto - what is it?
« Reply #34 on: 12.05. 2016 13:51 »
Yes this has been one of the more interesting posts
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 mikeb

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Re: strange goop in magneto - what is it?
« Reply #35 on: 16.05. 2016 08:59 »
reporting back: 400 miles on the 'new new' brushes (that is, the chamfered/rounded ones) and no more of that strange goop in the maggie. the slipring has some black on it which I assume is the new brushes wearing against the now rough slipring surface. still, the brushes look fine for now. I'll order a new slipring and put it on the 'to do' list (including the b33 that's quite a long list).

so... weird white nylon sliprings and square profile brushes do not play well together: avoid!

btw: the rally ride was great. great weather, 54+ classic bikes of all kinds, great roads and destinations. the a10 ran well on its first big post-rebuild ride with only a medium oil leak (the rocker feed take-off joiner failed) and a little oil leak (a seam on the oil tank is opening up thanks to incorrect mounting). its good to have it back on the road again.
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Offline duTch

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Re: strange goop in magneto - what is it?
« Reply #36 on: 16.05. 2016 10:37 »

 Mike, Good you had a trouble free trip, but with regard to
Quote
so... weird white nylon sliprings and square profile brushes do not play well together: avoid!

 I think the only way you'll know for sure is to put it all back as it was. Given that the brushes all wear down past square to having a 'slip-ring-radius' anyway, I'm not convinced those brushes are the disease. I may be wrong and happy to be proven so, but if they made the same marks as the others;-> *dunno*
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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