boyer running without battery help

hi all.

i have a commando im building and have a boyer ignition with sparx power box
im getting a good spark with a battery connected

i have a 650ss that i have running problems and took the power box off
the commando and put it on the dommie. witjlhout battery
the power box has a capacitor and when i kick it over
im getting full 13 volts from the power box/capacitor
but when i connect it to the ignition box and kick it i get 2- 6 volts.

i have put a battery on and now get a good spark.

is it just not possible to run a boyer without a battery
i dont understand where 6 or 7 volts disappears to as soon as i hook
up the power box and the boyer wont fire with 12 minimum.

has anyone else had this.

any help???? cheers

I can start my Victor with Boyer digital ignition and a larger than std capacitor, twin coils & spark plugs, I have the same Red box on my Commando but I have never been able to kick that one without a battery, but it will bump start without a battery. Just guessing but the extra cylinder must be a factor as the Victor is started at TDC and has two turns before a firing spark is created (its wasted spark as well but the first spark is at low compression whilst the valves are still open) , the Commando only has one turn before it gets to needing a firing spark and this compression will slow the crank down if it does not fire. The bump start must get the voltage up to allow the boyer to fire.

Even with the Victor starting with just a Cap I still add a battery as its just more reliable especially with full lighting and coming to a stop. I have used 2amp, 7amp and 10amp batteries and there is no difference.

kommando

thanks for your reply.

does your battery charge ok?? hopefully with the new powerbox
it will charge ok. previously i had just a rec/reg on there
and the battery kept running down hence trying to run it without a battery
maybe a mag is the way to go.

cheers

Either your Sparx is declining or you have saprophytic losses somewhere I your harness, especially likely if your harness is original. Try wiring a stand alone circuit with just the Sparx and the ignition system and see if that helps. If yes than you have a questionable harness, if no than you have a bad Sparx.

Boyer makes a Power Box that offers a dedicated circuit for the ignition with a voltage delay for the rest of the motorcycles electrics; it was designed to accommodate the older black box electronic ignition systems that aren't nearly as voltage tolerant as the current Micro Digital system.

RS

many thanks RS
will try that

Battery charges fine on both, Victor has the correct single phase alternator and the Commando has a 3 phase Lucas 180W alternator with a Wassell 3 phase rectifier and voltage control.

When a analog boyah gets less than ~10.5 v its little brain goes nutzo on timing, I think it advances too much for horrific backfiring till dying on the fly or no joy to start by foot. Boyah and most other ignitions only draw like 5 watts or a few amps so not much a drag on charging systems. One wire loose off a lucas alternator is not enough to keep a black boyah firing right with head light on at legal hwy speed, found out the hard way a number of time by me and by Wesley. A Capacitor acts exactly like a battery, with very fast charge and discharge. If alternator magnets are aligned to stator right the voltage spikes can hit about the time the boyah needs to fire and will w/o a battery or even a cap inline. Alas Cdo don't seem to come that way.

nortonfastback750 said:

hi all.

witjlhout battery
the power box has a capacitor and when i kick it over
im getting full 13 volts from the power box/capacitor
but when i connect it to the ignition box and kick it i get 2- 6 volts.

any help???? cheers

Click to expand...

Sounds like the power box can supply the 12v with no load conditions, but cannot do that with the Boyer connected. I 'd estimate that the Boyer would require several amps whilst providing current to fire the coils. With only the few revolutions provided by a kickstart, the energy from the charging system provided may not provide this hence the voltage drop. On kicking, what does your 12v supply from the power box measure, with no battery, no Boyer, but say with the lights switch on, or brake light on?
My rebuild has included a Boyer Power box, and I had thought about running without a battery. After reading all the posts about issues with ignition systems on bikes used on the road, I've fitted a small battery anyway, I think for non race applications, it is a reasonable thing to do.

many thanks old bloke. most helpful

i disconnected all the wires from the lighting and ancillaries and hey presto
got a spark so should start now.

update!!! got it running but now have head gasket leak
its only recently been fitted as the last one blew
this one is copper but is still leaking.