As the points open, the magnetic field
collapses. When this occurs. a very high voltage
(up to about 15.000 volts) is induced in the
secondary winding of the ignition coil. This
high voltage is sufficient to jump the gap at the
spark plug. causing the plug to fire.
The condenser assists the coil in developing
high voltage and also serves to protect the
points. Inductance of the ignition coil primary
winding tends to keep a surge ofcurrent flowing
through the circuit even after the points have
started to open. The condenser stores this surge
and thus prevents arcing at the points.
Transistorized Ignition Operation
The ignition system consists of 4 spark plugs,
2 ignition coils, an IC igniter unit and 2 timing
pickup units. Figure 9 is a diagram of the
transistorized ignition circuit for 2 cylinders.
The Kawasaki transistorized ignition system is
similar to a contact breaker point ignition
system. It works much the same, with these
a. Mechanical contact points are replaced
by magnetic triggering pickup coils. The
elimination of contact breaker points
means that periodic adjustment of point
gap and ignition timing are no longer
required. Once set properly. initial timing
should not require adjustment for the life
of the motorcycle.
An intermediate electronic switch. the
battery-powered IC igniter, receives the
weak signals from the pickup coils and
uses them t o turn the ignition coil
primary current on and off.
c. T h e ignition coil has a special low
resistance primary winding that helps it
produce a powerful spark at high rpm.
d. The transistorized ignition system's
slightly as engine
speed increases. This is a characteristic of
the magnetic pickup coils.
e. Ignition timing is not adjustable.
The ignition coil primary current is normally
off until the ignition timing rotor cam
approaches the pickup coil. As the rotor cam
approaches the pickup coil, a pickup coil signal
builds to a level that turns the IC igniter on,
allowing primary current to flow through the
ignition coil. As the rotor cam passes the
pickup coil. the trigger signal reverses polarity
IGNITION SYSTEM (TRANSISTORIZED)
Engine kill switch
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