--- In
DSN_klr650@yahoogroups.com, Devon
wrote:
> gary@s... wrote:
>
> >I believe the ignition draws from the battery a bit when it is at
low idle, ie it'll probably run without a battery just not well.
> >
> The KLR ignition is powered entirely by two windings on the stator
that
> are completely separate from the three windings for the charging
> system. The two systems aren't connected. Maybe a fresh battery
spun
> the motor faster and it started more easily.
>
> >In a car if you have a bad alternator it will run off the battery,
until you are driving with dim headlights in 3 feet of snow in
Vermont on a Sunday when the parts store is closed, but that's
another story...
> >
> Yes, but cars have points ignition, or the modern transistorized
version
> of it. This uses battery power to constantly energize the
ignition,
> until the points open (or the transistor shuts it off), collapsing
the
> field and causing a spark. Many bikes have the same system. I had
one
> which had the lovely quirk of happily cranking away with a battery
too
> low to power the ignition computer.
>
> KLRs, SR500s, DRZ400s, and many dirtbikes or dirtbike-based bikes
have
> CDI/magneto ignition, where the ignition is unpowered until the CDI
> fires, creating and collapsing the field and generating a spark.
The CDI
> is powered by the dedicated ignition windings.
>
> Devon
Hmmm. I'm sitting here looking at the wiring diagram (a CMC party
favor, thanks, Fred) and trying to reconcile this with what we
observed when a when a wire to the brake light switch came adrift on
a buddy's bike, shorted on the frame intermittently, and kept blowing
the main fuse. The headlight would go dim, while the bike would keep
running, but poorly, misfiring and not revving out completely. Of
course, with the battery out of it, the bike will not restart on the
button.
Blowing the main fuse obviuosly interrupts the battery feed to the
regilator/rectifier, leaving lights, etc to rely on current supplied
by the mag (3 yellow wires) to the r/r. It appears that the CDI gets
unrectified current from the mag (red wire). As you say, the ignition
is almost completely isolated, except that the ignition coil shares a
common ground with the charging system, through the (-) terminal of
the battery.
If the ignition were totally unreliant on battery power, I would
expect the bike to keep running well with a blown main fuse. Here my
ignorance of electrical matters overtakes me, but leaves me wondering
if this shared ground somehow affects the ignition when power from
the battery is interrupted. Or am I missing something?