Fig.
96.
Contact breaker
fective capacitor (initial stage). If several plies of thc
capacitor winding break dmm. the engine will be abie
to idle but will stall
\vhen
it
is accelerated (any at-
tempts to adjust thc carburetter will in this case be i~
\wn natu:.::l!\~).
Make,
,sure thc, earth contact 1s in or-
dcr
!
To adjust the contact-brcaker points gap. the crnnk-
shaft must be turned until the high-level portion of tht
cam
("0")
lifts the contact level.. The feeler gauge must
lightly contact both breaker points. in other words,
it
must not be tight or loose.
After loosening the setscrew
(3).
adjustments are made
by means of the eccentric screw
(4),
Fig. 96.
The specified gap is adjusted by turning the latter.
Then properly tighten the setscrew and once more
check the gap.
Contact-breaker points gap: 0.3'O.' mm
Measure the gap with particular care when the firing
point has already been timed and only the contact-
breaker points are readjusted.
Note:
If the contact-breaker points gap is increased, the
ignition is advanced (the cam starts lifting the con-
tact breaker at the beginning of the cam lobe); if the
contact-breaker points gap is reduced (due to wrong
adjustment or wear) the ignition is retarded (in this
case, the contact breaker only slightly contacts the
high-level portion of the cam. The ignition coil
is
not in a position to built up the required strong mag-
netic field, a weak spark will result
-
the engine
causes the carburetter to spit back).
Fig.
07.
Ignition setting gauge
H
8-1408-3
screwed
In
place
38
Screw
in place the ignition timing gauge 29-50.801
(spccial tool) or
a
similar gauge ensuring accurate
mei~surements (dial gauge).
5.4.2.1.
Ignition Timing
by
Means of a
Graduated Dial
If thc +.pc~ial tool "timing gaugc 29-50.801"
is
not availa-
blr.
a
graduated dial may bc used which can be
bought at any stationer's shop (teaching aid).
In ordri to bc in
;I
position to check the contact points
1:';1p
during
t
hc. timing opei.ations. the dial is provided
\\.~ti)
thccc. \\indo\vs (drill.
01.
lile them out).
Ti~c. pointcl.
(Z)
must bc at Ic.;ist 3.5 to 3 mm thick to
a\.oid
t
~ming cn.ol.s dw to inadvc.rlcntly bending it.
Flg.
!H.
Ignition
t~rninx
\vith graduated dial
A piwondition for the correct ignition timing is the
accurate determination of the top dead centre (T.D.C.).
For this purpose,
a
stop for thc piston must be prc-
pared (Fig. 99).
The,
stop is made of
a
useless sparking-plug by remov-
ing thc insulatoi and fitting
a
bolt in its place.
A
hole
is drilled in the sidc to allo\v thc compressed fuel-air
mixture to escape. The hole is drilled in the side be-
cause in the front part an
M-4
wtting screw should
be
scr.ewed in if required. In this way, the stop can also
bc used for other engines. After having tightened the
T.D.C. stop
(it
must not be loose!). turn the crankshaft
anti-clock\vise up to the stop. using the dynamo ar-
mature
scre\v
(1)
for turning
-
then record the de-
jirces indicated by the pointer. Prior to this adjust the
Fig.
99.
Stop for piston
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