Honda C50 - Spark Plug Reach; Spark Plug Electrode Diagram; Sooty Plug View; Overheated Plug View

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figure 5- 24. Spark p lu g r each
0
X
Standard reach
Reach too long
Figure 5- 25 . Spark plug elec t rode
figure 5- 26 . Sooty pl ug
Figure
5-27 . Overhe ated plug
5. ELECTRICAL SYSTEM
X
Reach too short
The correct spark plugs fo r the different mo del s
ore shown in Fig. 5- 23.
3. SPARK PLUG REACH
The reac h of the spark plug refers to length of
the thr eaded sectio n. Different mode l moto r cy cle s
hove
cy lind er head designed wi th different dep th of
spark plug hole, th erefore, the spark plug wit h the
proper reach shou ld be used. (Fig. 5- 24, 5- 25)
The
following unsatisfactory condi tio ns will occur
if plugs of improper reach ore used.
CD Reach t oo long
a. Carbon wil l be deposited on the exposed thread
and cause damages to the threads in the spark
plug
hole during p lu g remova l
b. The plug
tip w ill become over heat ed, ca using
p
re- ignit ion.
® Reach too short
a. Carbon wi ll be deposited on the threa ds at the
botto m of the plug hole and when the spark
plug
of the proper reach is install ed, the plug
hole threads will be damaged .
b. Du e to the cavity left by the s hort reach, ex-
ha ust gas will accumul ate causing decrease in
powe r outp ut, overheati ng, engine malfunc tion .
4. SPARK PLUG REACH
The s park plug firing, rega rd! ess of whet her the
primary power supply is from on A.C. Generator or
a D .C. source, is produced by the high vo l tage
secondery co il. The vol tage generated will vary with
the engine speed, h ow ever, wi th the . proper spark
gop, there is suffi cient vo l tage to produce a spark
for the required exp losi on . If the spark gop is too
wide , a very high vo ltag e is necessary to produce a
spark and, in w
hi ch case, a misfire wil l result at l ow
speed.
On the other hand, if the gop is t oo narrow, a
s
park w ill be pr od uced at a very l ow vo lt age and
since the spark will be of a l ow energy, on in co mple te
explosion wi ll toke place, resulting in engine ma lfunc-
tion.