Honda CB160 Shop Manual page 89

5.
3 IGNITION CIRCUIT
The breaker point consists of the breaker arm,
points (movable contact point and fixed contact point),
primary connecting terminal, spring, and oil felt coupled
on the base. The breaker arm is of bakelite including
rag. (In some cases, thin iron sheet, press-worked
products with a bakelite contact point {cam foll0wJ
at an end are employed). To either type, movable
contact point and other contact points are applied at
the ends and are insulated at the base. (Refer to
Fig. 5. 17)
The breaker arm performs light motion, and in order
to decrease inertia it must be compact, lightweight,
and rigid.
In order to prevent chattering at the time of breaker
point shorting, spring pressure must be sufficient. How-
ever, in order to prevent deviation of spark time to
sliding-section wear of the contactor, spring force
must be limited to some extent. Spring force gene•
rally ranges from
700
to
900
g at the contact point.
(Refer to Fig.
5.
18} (1.5 to l .98 lbl
In order to prevent wear at the sliding section of
the breaker arm, grease is applied to the oil felt on
the base, the axis oil groove, and the arm lubricator.
Inspection and lubrication is required, upon disassembly.
(Refer to Fig. 5. 19)
Lubricant to employ :
For the contact point of general automotive vehicles
tungsten material is widely used, and for the race,
soft platinum with superior conductivity is occasionally
employed.
{Refer to Fig. 5. 20)
• Contact point requirements
l.
It should be wear resistant.
2. It should be heat conductive.
3. It should have 2 sufficient melting points.
4. It should provide oxidation resistance.
5. It should not be easily inFluenced by water or 0il
6. It should possess sufficient hardness.
The point cams of Model CB
125
and CB
160
are set to the left of the camshaft. Both cams ore
coupled to the profile, spark advancer, and simul-
taneous spark system by the employment of one
breaker point, which means that one of the two
cylinders is released in a nonfunctional status.
Fig.
5.
17 Parts or breaker point
SPRING-
fig. 5.
18
SPECIFICATION
LIFTER PRESSURE:
800 GR± I 00 GR
POINT GAP: 0 .35±0 .05
INSULATION RESISTANCE:
MORE THAN IMO
POINT MA TERI AL:
TUNGSTEN
Breaker arm and spring
Service Values
Point pressure When less than 600g at lowest
value.
Point gap When impossible to adjust the gap
in the range of 0.25 to 0.4 after
using the spark advancer to cor-
rect the timing.
Insulation
resistance When less than 1
Mn
with a
Fig. 5. 19
500 V (or morel megger.
Value for maintenance and replacement
of breaker ·point
Fig. 5. 20 Breaker point
85