Honda CB160 Shop Manual page 88

84
INSULATING
PAPER
TIN FOil
Fig. 5. 13 Capacitor construction
Fig. 5. 14
Capacitor
fig. 5. 15
Capacitor testir,g
Fig. 5. 16
Breaker point
5.
ELECTRICAL PARTS
C. Capacitor
The capacitor avoids generation of harmful sparks
between points. That is, when high voltage is gene-
rated at the secondary coil of the ignition coil by
switching the points, additional voltage is generated
at the primary coil. (Self induction voltage). When
the primary current is disconnected, self-induction
~voltages tends to continue current transmission and
cause sparks between points. This results in burnt
points, a reduction of secondary coil, week voltage
ignition sparks, or causes fire. The capacitor absorbs
self-induction voltage quickly.
The capacitor employed in automotive vehicles
usually consists of a belt-shaped, thin metallic foil, and
insulation which are alternatively folded and rolled.
Electricity is stored in the capacitor when voltage
is
applied to the metallic fold. The larger the metallic
foil and the thinner the insulator, the greater will be
the capacity. When electrical capacity is excessively
large, spark performance is hindered. The correct
electrical value is generally between 0.1 to 0.35 F.
High voltage is applied to the capacitor when the
point is opened. In accordance to JIS the specified
voltage distribution value is: ·30 minutes after heating
at 80°C, the insulation resistance should be more
than 5 MO and should remain at this value in excess
of one minute at 700 VAC (50 to 60 cps). (Refer
to
Fig.
5.
13 and
5.
14)
To test the capacitor, both capacitor terminals are
:separated from the megger while the megger is rotat-
ing and then both terminals are shorted. If sufficient
sparks are generated, capacity value is considered
:iormal. A capacity change rarely occurs. Correct
capacity and insulat-ion value can be obtained by
.employing a service tester. (Refer to Fig.
5.
15)
D.
Breaker points
The breaker point interrupts the primary circuit of
the ignition coil or magnetic ignition coil. Generally,
in the case of the rotating magnet type, the contacl .
breaker is included in the body. In the coupled type,
the breaker point is coupled the stator, and in the
case of the separate type flywheel generator and
battery ignition system, the single unti type breaker
system is employed. In Models CB 125 and CB l 60,
the breaker point is installed to the right end of the
camshaft together with the spark advance mechanism.
(Refer to Fig.
5.
16)