Function Of The Respective Components; Main Jet; Air Jet; Needle Jet - Honda C50 Shop Manual

40
Main Jet
Figure 3- 96. Main jet
Figure 3- 97. Air jet
Figure 3- 98. Needle jet
3. ENGINE
5.
a .
However, depending upon its usage,
1 1
may result
in engine stalling or flo oding. To counter this situa -
tion, a relief val ve
@
is incorporated i n the choke
valve
@
to open or closes at a preset suction pr es-
sure, to produce a proper fuel air mixture for cold
w eather starting. It is therefo re possible to close the
choke valve completely during w arm-up driving and
en fully open the valve after warm-up. (Fig.
3- 95)
1 0 OF THE RESPECTIVE
COMPONENTS
o i j e
h e_
-·cs · ~e
= uel flow duri ng f ull throttle con-
di"ion ·oo s:::eec ·o provide a pro per f uel mixt ure.
Not o ly does ·. =.;"cion a top speed but also is
effective o a ce
· a·~
degree oi int ermediate speed.
The larger he ·e size mumber, g reater w i ll be
the fu el flow a ·o "cfng a rich er fuel mixture .
(Fig.
3-96)
b. Air
j et
During full throttle o pe ning, t he fuel mi xt ure at
high e ngine speed will become rich and at slow
engine speed he mixture becomes leon. To prevent
such a condition, air is bled i nto th e mai n jet. The
function of the air jet is to restrict the a mount of air.
As the a ir jet is mode larger, the amount of air is
increased, resu lting in a leo n fue l mixture, however,
at the t hrott le openi ng, a high engine speed will
provide a lean mixtur e with a sma ller variation i n fue l
consumption between high a nd low engi ne speed.
(Fig .
3- 97)
c. Needle jet
During full o r half thro ttle opening, the fuel which
hod been metered by th e mai n jet i s again
~tered
by the needl e jet. The adjustment is performed in
con junctio n with the jet need le which is explain i n the
fo ll owing section. The nee dle ho le is modA exce p-
tiona lly accurate. (Fig. 3- 98)