Read this first

Here are some quick answers to your questions. I hope I use the right
terms. I only have practical knowledge of the system, so just tell me if I
am unclear.

1 - Components
One complete set of these electronic ignition consists of:
- One tiny mechanical assembly (which I will call a finger). It is rigged
to the crankshaft; its function is to give the timing, and it is spring
loaded to cater for advance/retard variation at start-up;
- Two tiny magnetic sensors (with two wires each); these are rigged to the
engine block, with a bracket, and are placed around the crankshaft,
(around the finger). They are horizontally opposed (180°). When the finger
passes by, they trigger.
- Two "relays" (with five wires each) The function of these is to open and
close the power supply to the coils, when the magnetic sensors tell them
- Two coils . Note that these coils have two spark plugs lead each.
- Four spark plugs.
I haven't opened the magnetic sensors housings, nor the relays housings.
But considering that the magnetic housings are half the size of a matchbox
and the relays the size of a matchbox, there can't be too many components
in them.

3 - Crankshaft attachment
The mechanical assembly is bolted to the crankshaft. The magnetic sensors
are rigged to a plate, which is attached to the engine block through a
bracket with long legs.

4 - Timing pickup
I already answered that, but I should elaborate a little bit more. The
solid rigging ensures precise timing. Once you are happy with the timing,
you tighten the bolts, and the timing stays like that forever. Only at
start-up, the advance is less, to prevent kick-back. Then the engine
starts, and the centrifugal force makes the finger fight its spring, and
it assumes correct timing position.
Every half turn of the crankshaft, one of the two magnetic sensors closes
the relay, and as a consequence, two spark plugs fire. One fires at the
right timing (ignition), the other fires at the wrong timing (exhaust
phase). So, only one serves a purpose, but the system is made more simple

6 - They come straight from.......; What make and model cycle
Honda CB series, circa 1980 or so. I am not 100% sure. When I decided to
expand the system, I took my parts to a bike junkyard, and asked them to
give me the same ones. There were many look-alikes to choose from, because
most Japanese 4-cylinder bikes of that time used the same set-up.

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