Author Topic: Magneto only sparks on one side...  (Read 1138 times)

Online JulianS

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Re: Magneto only sparks on one side...
« Reply #15 on: 17.07. 2020 12:08 »
The original Lucas pickups had mazac internals. You usually see the mazac tunnel for the brush about 2 mm below the nose ofthe pickup.

Photo shows a cranked pickup less the bakelite.

Dont know about the white box items.

Offline Swarfcut

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Re: Magneto only sparks on one side...
« Reply #16 on: 17.07. 2020 18:11 »
 Well I never! So that's how they do it,  Thanks Julian, another mystery solved. Maybe the change in crystalline structure of that cheapo alloy accounts for a lot of our mysterious electrical gremlins. Any metallurgists in the house?

 Swarfy.

beezermacc

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Re: Magneto only sparks on one side...
« Reply #17 on: 17.07. 2020 19:29 »
I find they oxidise on the surface, preventing continuity, but can be cleaned up with a drill, then usually OK. The HT current will arc through the oxidisation but it is essential to achieve continuity before fitting just in case there is a more serious break somewhere else.

Offline RogerSB

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Re: Magneto only sparks on one side...
« Reply #18 on: 17.07. 2020 21:36 »
In 2018 I fitted mag brushes from Brightsparks after first buying Lucas (Wassell) ones, which I didn't use as I could draw with them like charcoal. I complained to Wassell and received the expected reply.

Topic is found here: https://www.a7a10.net/forum/index.php?topic=13086.msg105623#msg105623

I've attached the letter I sent to Wassell and the drawing test here.

At that time it always took me several good kicks to get my bike going, afterwards and since then it very rarely takes more than two. Usually half a step on the kick start to prime a good kick and away she goes.

Also around that time I started to use premium petrol, and started to add some Redex Lead Replacement, Carb Cleaner and Sta-Bil 360 Marine Ethanol Treatment and I'm sure that's also helped.

1960 Golden Flash

beezermacc

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Re: Magneto only sparks on one side...
« Reply #19 on: 18.07. 2020 09:24 »
With reference to RogerSB's message above... The 'Lucas' brushes and pickups supplied by Wassell are usually OK. The black lines are caused by loose residue on the brushes which soon wears off. I always rub them on some very fine emery before using them and I have never had a problem.

Offline RogerSB

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Re: Magneto only sparks on one side...
« Reply #20 on: 18.07. 2020 13:19 »
With reference to RogerSB's message above... The 'Lucas' brushes and pickups supplied by Wassell are usually OK. The black lines are caused by loose residue on the brushes which soon wears off. I always rub them on some very fine emery before using them and I have never had a problem.

I'm glad you mentioned that Andrew. I knew that, but maybe some didn't know.

(Edit) Here's another example:-
Look at the photo carefully and you will see that the Lucas face has actually been overprinted on one that originally was printed Royal Enfield. My camera showed it up as it's not visible with the naked eye. It puzzled me at first and then it dawned on me and I went looking and came across this horrible cheapy one for under £8.00 which shows the exact design that is under-printed on the Lucas branded one *pull hair out*.

It was returned to the seller.

(Edit - again): Maybe all Lucas branded components we buy are not the same  *cry*

1960 Golden Flash

Online RDfella

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Re: Magneto only sparks on one side...
« Reply #21 on: 18.07. 2020 16:50 »
Like all other producers that you could rely on, Lucas went to the dogs. Didn't they become Delphi at one time? As far as I know they're now an Indian firm, hence the Enfield connection.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

beezermacc

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Re: Magneto only sparks on one side...
« Reply #22 on: 18.07. 2020 17:45 »
Well spotted RogerSB. Reminds me of the saying  ".....be sure your sins will find you out...!"

Offline Bellanca A10

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Re: Magneto only sparks on one side...
« Reply #23 on: 18.07. 2020 17:52 »
These pick ups are the “black whole” type. The carbon brushes are loose inside their little bore-not confidence inspiring. My mag uses the screw on pick up. One of the previous posts mentioned that there was less choice of quality screw on styles?
The photo I posted shows the suspect pickup housing may actually, will soon have been, rubbing on the slip ring.
I searched for awhile from different parts distributors and none of the screw on pickups seem to be the good quality ones. I ended up just ordering another pair that look to be a different casting compared to the malfunctions one. The internal part of the new pickups appear (Judging from the online catalog photo) to have the shorter housing as does my good pick up.