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spark plugs

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Morala:
I have a 1974 cb550k which has a boyer ignition fitted, i was led to believe that the ignition fired all 4 plugs at the same time if this is the case the silly question is does it matter what plug leads go to a particular plug regarding firing order thanks for any advice.

McCabe-Thiele (Ted):
Yes it does as each pair of coils have to be connected in the correct firing order as dictated by the camshaft that is running at half crank speed.
It does not fire all four plugs at the same time, for a given coil there is a wasted spark, i.e. it sparks on compression on cylinder1, it also sparks  on cylinder 3 that is on the exhuast stroke (wasted spark). Similarly the other coil sparks when cylinder 2 is on compression. the wasted spark is on cylinder 4 on the exhuast stroke. This repeats itself on the next cylinder rotation to fire on 3 & 4.

Two sets of points control the two coils from the lobe at the end of the crank, the Boyer system emulates the points, if it fired all four at the same time you would be igniting fuel on the induction stroke as well as firng a cylinder on compression.

K2-K6:
The Boyer (later iteration) do fire all four plugs simultaneously and noted in their instructions.

It "shouldn't" matter in which way they are connected from this as asked by OP. I’ve not set one up in contrary fashion, so no direct experience of doing it wrong, as it were.

They don't disclose if there's parallel switching hardware, then to trigger both discreet output for the two coil OR if there's one switch set, triggered by both trigger set. I'd have thought the first would give redundancy to switching and logic, with the second giving some half redundancy to trigger hardware.

My inclination and experience to set them conventionally (1&4 / 2&3) coils to plug arrangement, and conventional to most bike like this, is more to save confusion in diagnostics etc, even if it was not me looking to fault find. But if there's good reason to go against that, it would be simply a test of function in verification. 
Its also unconventional in tbat it has no advance, just static at full "advance" mechanical position, then to retard within onboard electronics based on rpm trigger read to give low speed notional timing, this effectively set back from that static setting. That too leading to the final setup instructions of checking the timing dynamically and above tbe rpm at which the "advance" attribute plays out. Technically that's good, as full advance is more critical in cylinder performance and safety aspect.

It seems a quirky system, but really with very good logic, just appears different when judged against the conventional.

McCabe-Thiele (Ted):
So the Boyer ignition is firing not just on a cylinder compression, it also fires part way through the induction cycle. Would that not cause premature burning in a cylinder part way through the induction cycle of a four stroke engine, with the inlet valve open that would create a risk of fuel burning back into the carburettor. That sounds like serious built in pre- ignition.

An extra spark on the exhaust cycle, I can accept that as it's not burning fresh fuel.

Sesman:
Hi, Ted. I’m not an authority on the topic, but I’d imagine that without a complete induction cycle including compression there would be no risk of premature ignition. The spark is as they say…wasted.

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