|Magnetos contain a permanent magnet to produce the magnetic
field which, combined with the motion of the armature, produces the
electricity for the sparks. When the magneto left the factory, the magnet
would have been fully charged. However, despite being called 'permanent',
permanent magnets do lose strength with, for example, use, age, temperature
vibration. The magnet in a 1950s magneto typically now has only
about 70% of its initial strength.
You can find out more in our FAQs.
Two main effects of reduced magnet strength are:
The strength of spark is reduced.
Tests we have carried out show that the sparking plug current†
at a particular magneto speed is roughly directly proportional to the
magnet strength. So, if your magnet is 70% of full strength, your spark
current is about 70% of full strength.
(† Here we were
measuring the DC component of the HT current immediately after the spark
minimum speed required to produce sparks is increased.
Our tests suggest that the minimum speed‡
to produce sparks is roughly inversely proportional to the magnet strength
to the power 3/2. So, if your magnet has decreased to 70% of full
strength, the speed at which you need to kick over the engine to obtain
sparks is about 70% higher.
(‡ Here we were
measuring the magneto speed to obtain 95% of sparks with a 3-point spark
gap set to 5.5 mm at atmospheric pressure.)
However, it is possible to restore the magneto's magnet to its initial
strength by exposing it to a very strong magnetic field - remagnetisation.
Brightspark Magnetos is now able to offer a remagnetising service, using
our specially-developed remagnetising and measuring equipment to help you
restore your magneto to tip-top condition.
measuring magnetic flux density at the centre of the armature cavity
... with magneto body in place
|So, we will measure the initial strength of your magneto's
magnet and its polarity, remagnetise it with the same polarity
(unless you ask us to reverse it), measure the
resultant magnet strength, and send your magneto back to you with a report.
Initially, this service is offered only for instruments having a 2-inch
or 2-11/64" diameter armature (which covers most Lucas and BTH magnetos). Because of possible customs difficulties, we
regret that we are unable to provide this service to customers outside the
N1, KN1, K1F, K2F and KVF magnetos and
MO1L and MN2L magdynos, we can remagnetise the bare body without you
needing to send us the whole magneto. However, for some other magnetos and
magdynos which should not have the armature removed after remagnetisation,
it is better if you send us the whole magneto.
The cost is GBP 18
for remagnetising a bare magneto body inclusive of packing for return, plus return postage
at cost; or GBP 22 if you send us the complete magneto. Terms and conditions apply (see below).
Customers requiring the remagnetisation service should in the first instance contact us
by e-mail at
. We can entertain inquiries in
English or French.
- Your name, full address and telephone number.
- The make and model of magneto to be remagnetised.
- The state of disassembly in which the magneto will be sent to us (e.g.
bare body, or complete with armature and end housing)
- Whether you will also require any EasyCaps, and if so how many of each
- The postal service you wish us to use to return the item to you (e.g.
Royal Mail Special Delivery, or First Class Packet). You can check Royal
Mail and Parcelforce prices
We will then email you with a confirmed cost, payment details, and the
address to which to send your magneto or magneto body.
Nos clients, désireux de tels services, doivent nous contacter avant
tout par courriel à l’adresse suivante :
Nous pouvons vous aider soit en français, soit en anglais, à votre
convenance. Merci d’indiquer dans votre courriel :
- Vos nom et prénom, adresse complète & n° de téléphone.
- La marque & le modèle de votre magnéto.
- Si vous allez nous envoyer la magnéto entière, ou seulement sa
- Si vous avez besoin d'un (ou plus) condensateur(s) « EasyCap »
et si « oui », quel(s) modèle(s) & combien ?
- Le service de la Poste que vous choisissez pour le retour de
votre magnéto à partir de notre point de collecte en France. Pour
vous aider, voir:
Suite à la réception de ces renseignements, nous vous enverrons
notre prix ferme, l'adresse à laquelle envoyer vos pièces et vous
préciserons nos modalités de règlement.
Although we make no guarantees, we aim to send remagnetised magnetos back
no more than two working days after receipt, and in many cases the same day.
For UK customers, this therefore means that you can remove the magneto from
your motorcycle one weekend and probably have it remagnetised and ready to
replace the following weekend.
Terms and conditions for Brightspark remagnetising service
|Delivery to us:
||Customers are responsible for delivery to us, and
we do not accept any responsibility for loss of, or damage to, the item
in transit to us. We strongly recommend that customers use an insured and
signed-for service (such as Royal Mail Special Delivery in the UK). However,
in the event of loss or damage, we will provide all reasonable assistance to
a customer in making a claim against the delivery service.
||The fee of GBP 18 is for remagnetising a
magneto body supplied to us bare (apart from possibly including the
outer-race of the drive-end bearing and oil seal). If a magneto is supplied
to us with armature and end housing in place, we charge an additional fee of
GBP 4 for disassembly and reassembly, but we will also grease the
bearings, clean the slip ring and include in our report any comments on the
state of the instrument.
|Return post and packing:
||Our packaging charge is included in our
basic price. We will return items using whichever postal
service our customer requires, and we will charge postage at cost. We do not accept
any responsibility for loss of, or damage to, the item during
return to a customer. However, in the event of loss or damage, we will
provide all reasonable assistance to a customer in making a claim against
the delivery service.
||All payments are to be made either in GB pounds
cheque, bankers draft, British postal order, International money
order in GB pounds, or bank transfer) or in Euros (by cash,
cheque, bankers draft or bank transfer). Magnetos will not be
returned to customers until full payment has been received.
||The remagnetisation service is only available
to customers in EU countries.