Flywheel/Encoder patterns

[Chris Morriss]

In message <2.2.16.19961222141854.268f88b2 at mail.vt.edu>, Stephen
Dubovsky <dubovsky at vt.edu> writes
>
>Im not sure the plug in the exhaust stroke actually arcs over in a twin plug
>system.  Most (if not all new inline-4?) motorcycles the 2 coil w/ twin
>secondary arangement you are talking about.  I haven't tried it myself, but
>a good friend (and the shop book) says you dont get an extra spark when
>using a timing light.  I think the principle is that the cyl in the
>compression stroke will arc over first so the breakdown voltage of air will
>not be reached in the other cyl.  This should work well if the plugs are
>gapped similar and everything else is working right.  A stock kawi or honda
>will rev to 14k+ rpm before the rev-limiter comes in.  I just dont think you
>have to worry about ignition system life when this makes things so much
>simpler...
>Enjoy,
>SMD
>
>
It has to spark!  Effectively the two gaps are in series, even though
the plugs are connected to opposite ends of the coils.

BTW, the PD required to form a spark in the cylinder under compression
is higher than that for the cylinder at ambient pressure.  I'm not sure
how much the firing voltage increases with pressure but I'm sure someone
here probably does.
-- 
Chris Morriss