Service manual
SERVICE
MANUAL
- 19.75 SCORPION BRUT
440
Engine
Ignition:
Electrical
energy
(high
voltage,
low
amperage)
is
generated
by
rotating
a
permanent
magnet
flywheel
past
a
pair
of
ignition
coils.
The
high
voltage
(~200v)
thus
generated
is
absorbed
by
a
large
condenser.
A
special
signal
is
also
initiated
by
the
rotating
magnet
which
closes
an
electronic
switch
(tran
-
sistor)
every
120
degrees
of
rotation.
When
the
transistor
conducts,
current
flows
from
the
con
-
denser
through
the
primary
windings
of
the
three
external
coils.
The
current
rises
abruptly
as
the
condenser
discharges
creating
the
necessary
force
field
in
the
external
coils,
and
falls
just
as
abruptly.
The
voltage
induced
in
the
secondaries
of
the
external
coils
rises
so
rapidly
that
it
will
exceed
the
voltage
necessary
to
jump
the
spark
plug
gap
even
when
the
plugs
are
fouled.
All
three
plugs
"fires"
simultaneously
every
120
degrees.
Timing
of
cylinder
pressure,
however,
determines
which
one
of
the
three
cylinders
supports
combustion.
The
keyed
relationship
between
the
crankshaft
and
the
rotor
determines
the
timing
of
the
engine.
The
timing
is
electronically
advanced
progressively
from
start-up
to
fully
advanced
at
4500
RPM.
At
4500
RPM,
the
lead
is
between
3.2
and
3.5
mm.
This
corresponds
to
16
degrees
-
20
degree
advance.
NOTE:
The
Brut
440
ignition
schematic
is
not
accurate
physically,
but
only
intended
as
a
pictoral
representation
of
the
ignition
principles
involved.
MAIN
ELEMENTS:
1.
Magneto
Coils
a.
Ignition
Coils
b.
Signal
Coil
2. CDI
Unit
3.
External
Coils
4.
Spark
Plugs
3-6
CONDENSER
_L
(CDI UNIT)
TRANSISTOR
(CDI UNIT)
,--------~-------..
.,-----...
COILS
(MAG-
NETO)
SIGNAL COIL
(MAGNETO)
BRUT
440
IGNITION
SCHEMATIC
FIG. 3-9
EXTERNAL
COILS
(3)
SPARK
PLU(~
I•
I·
_)
J