Help,
Just fitted a Boyer Bransden MK3 to my BS B50 72MX but can't work
out how to get it to fire without a battery and buying a rectifier ( was
energy transfer system with half size stator).
Was I sold the wrong one or is this just the way? Can it be done without a
battery? Only two wires from stator and never had a rectifier with standard
system.

Any help much appreciated. I live far away from major city not much to
resource help here.

Dave

B50 MX
Trident 900

"Dave Haig" <(E-Mail Removed)> wrote in message
news:1RB6b.87304$(E-Mail Removed)...
> Help,
> Just fitted a Boyer Bransden MK3 to my BS B50 72MX but can't work
> out how to get it to fire without a battery and buying a rectifier
was
> energy transfer system with half size stator).
> Was I sold the wrong one or is this just the way? Can it be done without a
> battery? Only two wires from stator and never had a rectifier with
standard
> system.
>
> Any help much appreciated. I live far away from major city not much to
> resource help here.

Everything I've ever read about Boyer says you'll have to run a battery to
use it. That's the main reason I won't use Boyer on my bike.

Les
'70 TR6R "Layla"
http://www.triumphchoppers.com

"Les" <(E-Mail Removed)> wrote in message
news:BKS6b.154013$(E-Mail Removed) ...
>
> "Dave Haig" <(E-Mail Removed)> wrote in message
> news:1RB6b.87304$(E-Mail Removed)...
> > Help,
> > Just fitted a Boyer Bransden MK3 to my BS B50 72MX but can't
work
> > out how to get it to fire without a battery and buying a rectifier
> was
> > energy transfer system with half size stator).
> > Was I sold the wrong one or is this just the way? Can it be done without
a
> > battery? Only two wires from stator and never had a rectifier with
> standard
> > system.
> >
> > Any help much appreciated. I live far away from major city not much to
> > resource help here.
>
> Everything I've ever read about Boyer says you'll have to run a battery to
> use it. That's the main reason I won't use Boyer on my bike.
>
> Les
You can, however use a large low-ESR capacitor in place of the battery - BSA
did this on some of the competition bikes in the 70's. An audio-grade 68000
uF 25 Volt electrolytic should do the job - damn sight lighter than a
battery, too! You'll *definitely* need a rectifier, as the Boyer needs DC to
power it, and AC will kill it dead instantly. The capacitor will go
*BANG!!!!!!!!!!!!!* and shower you with caustic electrolyte if connected to
AC, too )
HTH,
Dave H.
(The engineer formerly known as Homeless)

"Dave H." wrote:
>
> "Les" <(E-Mail Removed)> wrote in message
> news:BKS6b.154013$(E-Mail Removed) ...
> >
> > "Dave Haig" <(E-Mail Removed)> wrote in message
> > news:1RB6b.87304$(E-Mail Removed)...
> > > Help,
> > > Just fitted a Boyer Bransden MK3 to my BS B50 72MX but can't
> work
> > > out how to get it to fire without a battery and buying a rectifier
> > was
> > > energy transfer system with half size stator).
> > > Was I sold the wrong one or is this just the way? Can it be done without
> a
> > > battery? Only two wires from stator and never had a rectifier with
> > standard
> > > system.
> > >
> > > Any help much appreciated. I live far away from major city not much to
> > > resource help here.
> >
> > Everything I've ever read about Boyer says you'll have to run a battery to
> > use it. That's the main reason I won't use Boyer on my bike.
> >
> > Les
> You can, however use a large low-ESR capacitor in place of the battery - BSA
> did this on some of the competition bikes in the 70's. An audio-grade 68000
> uF 25 Volt electrolytic should do the job - damn sight lighter than a
> battery, too! You'll *definitely* need a rectifier, as the Boyer needs DC to
> power it, and AC will kill it dead instantly. The capacitor will go
> *BANG!!!!!!!!!!!!!* and shower you with caustic electrolyte if connected to
> AC, too )
>

It goes BANG when the wire slips off of the zener.

With points, you may be able to continue without
the capacitor by reconnecting the zener.
It all depends on the points breaking near a
voltage peak in alternator output.