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Lucas K2F magneto coil rewind

A pensioner has asked me about possiblity of rewinding some of these magneto coils.

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laying on cm/mm graph paper. Orangey section is the laquered coil. C area is the contact patch (supplying 2 HT leads in turn) moulded into the surrounding paxolin? insulation, continued out to the boss marked P, but otherwise looking like the tarnished brass sections in colour , marked B. The curve above the C is the shape of one end of this contact section, not a trick of the light. A is aluminium housing for the contact breaker First comment is he has 5 of these , all not working at all or properly, so probably not good design anyway, as none were abused in use. He has one good magneto , he moves around 3 bikes. He can get some or all nonworkers commercially reconditioned , at a price each. But of course he would like all 5 rewound and he knows, like me , that having researched and set-up for one then the following 4 rewinds are much easier. I use a coil-winder machine but little experience of these sorts of coils. No electrical data found on the net for these. As received by me, the secondary measured 22K ohm, now reads 6.3K , at this stage, presumably shorted turns rather than a break for this one. He has some sort of technical data for these , when he can find it, but first thing is how to (after desolding) slide the laquered-in coil out of the central section between the 2 steel pole pieces marked S, and because of the boss marked P that holds the HT wire lead out, coil would have to be removed from the other open section, underneath in pic. Anyone know the number of turns, wire gauge to save having to count off ? and details of interlayer insulation (if any). How is the HT coil output removed from the boss P or whereabouts is the join to a feedthrough under the output laquer?

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N_Cook
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On Thu, 24 Apr 2008 11:39:33 +0100, N_Cook wrote in :

You don't say what make it is, nor which bike(s) it fits.

A quick educated guess, and I found a very similar device here:

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-- Lucas K2F. The company claims to have a complete reconditioning service.

There's an exploded view here:

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-- sounds like disassembling the armature is best left to someone experienced.

Workshop manual here:

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One particular item was: primary 20 g 4x45T; secondary 40 g ~30x250T by the looks of it:

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Ivan Reid, School of Engineering & Design, _____________  CMS Collaboration,
Brunel University.    Ivan.Reid@[brunel.ac.uk|cern.ch]    Room 40-1-B12, CERN
GSX600F, RG250WD         "You Porsche. Me pass!"   DoD #484     JKLO#003, 005
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Reply to
Dr Ivan D. Reid

On Thu, 24 Apr 2008 11:39:33 +0100, N_Cook wrote in :

[Idiot; Read the Subject line]

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The company claims to have a complete reconditioning service.

There's an exploded view here:

formatting link
formatting link
-- sounds like disassembling the armature is best left to someone experienced.

Workshop manual here:

formatting link

One particular item was: primary 20 g 4x45T; secondary 40 g ~30x250T by the looks of it:

formatting link 

--
Ivan Reid, School of Engineering & Design, _____________  CMS Collaboration,
Brunel University.    Ivan.Reid@[brunel.ac.uk|cern.ch]    Room 40-1-B12, CERN
GSX600F, RG250WD         "You Porsche. Me pass!"   DoD #484     JKLO#003, 005
WP7# 3000   LC Unit #2368 (tinlc)   UKMC#00009   BOTAFOT#16    UKRMMA#7 (Hon)
        KotPT -- "for stupidity above and beyond the call of duty".
Reply to
Dr Ivan D. Reid

This is the kind of question you could well ask in the newsgroup uk.rec.sheds. There are a lot of old motorbikey/engineery type folks hang out in the shed.

Ron

Reply to
Ron(UK)

magneto

the

B.

not a

so

all

he

and

this

of

because of

the

laquer?

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38/p/1.html

Collaboration,

CERN

005

(Hon)

Ta for that, i'd not found that pdf I suspect the owner has a paper version of that pdf

Perhaps 40 awg in that thread , I would expect from previously winding outboard engine magnetos that it was more like 45 swg gauge. Every time I touch this armature the secondary ohms varies, 45K and 27K on the last 2 occasions, so at least cannot make matters worse. I wonder if you have to remove the pulley-like paxolin drum numbered 27 on that pinman pic, before releasing the internal HT leadout, to then remove the coil. I can now see how to remove the coil assembly but not how that leadout is connected into the paxolin drum. I can see me using glass tape being used instead of cloth for outer protection, for anti-hygroscopic reasons.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N_Cook

magneto

the

B.

not a

so

all

he

and

this

of

because of

the

laquer?

u.r.s added

From the Lucas pdf , under fig 6

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"Fit the new slip ring moulding on the shaft, taking care that the wire enters the hole in the slip ring boss , and that it goes fully home without bending. Seal the wire into the bosss with varnish"

Sounds a bit odd and don't know what it means yet, pushfit and varnish?.

The contact breaker housing comes off by slackening the central holding bolt a bit and lightly tapping the bolt head to release a keyed bushing.

It looks as though a roll pin passes through both steel cheeks and through the coil bobbin to hold the coil in place. I've not managed to shift that with my usual use of bits of pop-rivet steel pin, so far. One hole is slightly larger than the other and I'm assuming its a matter of knocking the pin through the small hole of about 2.2mm diameter to release through the larger 2.5mm hole.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

formatting link

Reply to
N_Cook

magneto

the

B.

not a

so

all

he

and

this

of

because of

the

laquer?

u.r.s added

From the Lucas pdf , under fig 6

formatting link
"Fit the new slip ring moulding on the shaft, taking care that the wire enters the hole in the slip ring boss , and that it goes fully home without bending. Seal the wire into the bosss with varnish"

Sounds a bit odd and don't know what it means yet, pushfit and varnish?.

The contact breaker housing comes off by slackening the central holding bolt a bit and lightly tapping the bolt head to release a keyed bushing.

It looks as though a roll pin passes through both steel cheeks and through the coil bobbin to hold the coil in place. I've not managed to shift that with my usual use of bits of pop-rivet steel pin, so far. One hole is slightly larger than the other and I'm assuming its a matter of knocking the pin through the small hole of about 2.2mm diameter to release through the larger 2.5mm hole.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

formatting link

Reply to
N_Cook

magneto

the

B.

not a

so

all

he

and

this

of

because of

the

laquer?

u.r.s added

From the Lucas pdf , under fig 6

formatting link
"Fit the new slip ring moulding on the shaft, taking care that the wire enters the hole in the slip ring boss , and that it goes fully home without bending. Seal the wire into the bosss with varnish"

Sounds a bit odd and don't know what it means yet, pushfit and varnish?.

The contact breaker housing comes off by slackening the central holding bolt a bit and lightly tapping the bolt head to release a keyed bushing.

It looks as though a roll pin passes through both steel cheeks and through the coil bobbin to hold the coil in place. I've not managed to shift that with my usual use of bits of pop-rivet steel pin, so far. One hole is slightly larger than the other and I'm assuming its a matter of knocking the pin through the small hole of about 2.2mm diameter to release through the larger 2.5mm hole.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

formatting link

Reply to
N_Cook

magneto

the

B.

not a

so

all

he

and

this

of

because of

the

laquer?

u.r.s added

From the Lucas pdf , under fig 6

formatting link
"Fit the new slip ring moulding on the shaft, taking care that the wire enters the hole in the slip ring boss , and that it goes fully home without bending. Seal the wire into the bosss with varnish"

Sounds a bit odd and don't know what it means yet, pushfit and varnish?.

The contact breaker housing comes off by slackening the central holding bolt a bit and lightly tapping the bolt head to release a keyed bushing.

It looks as though a roll pin passes through both steel cheeks and through the coil bobbin to hold the coil in place. I've not managed to shift that with my usual use of bits of pop-rivet steel pin, so far. One hole is slightly larger than the other and I'm assuming its a matter of knocking the pin through the small hole of about 2.2mm diameter to release through the larger 2.5mm hole.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

formatting link

Reply to
N_Cook

"There's yer problem right away, guv. You should be measuring yer hole in 64ths of an inch for a Lucas"

Reply to
bobharvey

On Thu, 24 Apr 2008 19:17:51 +0100, "N_Cook" wrote and included this (or some of this):

Oo-er Missis.

--
®óñ©  ©  ²°¹°-°³

Insanity is doing the same over and over again and 
expecting a different result.   Einstein.
Reply to
®óñ© © ²°¹°-°²

to

e
a
o

he

d
s

of

?

I hope you are either doing this as a HUGE favor for the pensioner, or he/she is rich enough to pay you adequately for your time. No matter how you get it apart, it will be a large royal pain to rewind with that fine/small size wire and then reconnect the wire to the slip rings. Any idea why so many of these hae failed, it might tell you what not to do when rewinding.

Reply to
hrhofmann

The K2F magneto. Blimey, I haven't even heard of that since I had one on a Matchless G12 in 1972.

And they say abfgnytvn isn't what it used to be.

Steve

Reply to
shazzbat

magneto

the

a

so

and

this

of

laquer?

on

formatting link

I hope you are either doing this as a HUGE favor for the pensioner, or he/she is rich enough to pay you adequately for your time. No matter how you get it apart, it will be a large royal pain to rewind with that fine/small size wire and then reconnect the wire to the slip rings. Any idea why so many of these hae failed, it might tell you what not to do when rewinding.

I was quite happy putting on about 14,000 turns of 45 swg wire onto boat outboard motor magneto coils, once the traverse rate, reducing endstop/reversal points etc was set up for my 1920s coilwinder , rusted and totally seized but now rescued back into working order after decades in someone's damp and leaking shed

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N_Cook

This magneto was fitted to quite a lot of British bikes from the 50's and early 60's. Myself, I'd find a professional restoration service to do the job. Safer in the long run, I think. Sorry, I can't help with a service manual. Colin

Reply to
Colin Horsley

Ah! Are you available for alternator rewinds?

--
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chateau dot murray at idnet dot com
"What you\'re proposing to do will involve a lot of time
and hassle for no tangible benefit."
Reply to
The Older Gentleman

OK this magneto has been in an English shed for years, but "isolating" secondary and putting a Megger between HT coil and frame shows 5M ohm to start with , drifting up to 100M , no good with intended KV around.

The capacitor, sorry, condenser measures 0.36uF which is presumably about right value, anyone know what value and type of capacitor to replace it with ?

Still not managed to free the bobbin retainer roll pin yet though

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N_Cook

In article , N_Cook writes

You didn't say: I assume from the pics that the wire is merely varnished, but is it cotton or silk covered too? if so, it may well be breakdown through damp.

Put it in the oven at around 50deg C for a few hours (days?) and try again.

Regards,

Simonm.

--
simonm|at|muircom|dot|demon|.|c|oh|dot|u|kay
SIMON MUIR, BRISTOL UK
EUROPEANS AGAINST THE EU                   http://www.eurofaq.freeuk.com/
GT250A'76  R80/RT'86  110CSW TDi'88  www.kc3ltd.co.uk/profile/eurofollie/
Reply to
SpamTrapSeeSig

Not rollpin , a matter of removing the ballrace and underlying steel rings and spacer from the brass section marked BR on

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requiring making up an extractor as standard pullers have no ledge to purchase on. The 2 long screws go the length of the steel pieces like an electric drill housing. Marked the orientation before removing the end cap. Yes the HT wire marked W just pushes into the boss of the paxolin pulley shown in the third pic. An excellent site for damp ingress , via capillary action, into the body of the coil (my excavations exploring how deep the cloth covering was). Green corrosion on the HT wire is more obvious in the original high resolution pic, evidencing dampness at the end of the HT sleeving.
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the capacitor is the square lump covered in greasy mess in the end cap
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the paxolin pulley-like section that goes on the brass axis at W position.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N_Cook

Before excavating further decided to take a pic of the now obvious ingress of damp down the HT wire. Lovely green copper carbonate staining.

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and the other cap interior where the contact breaker connection is from the centre fixing , insulated under and around , by what looks like a black RF coil former
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-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N_Cook

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