Carburetor (S50, S65) Diagram; Air Flow; Fuel Flow - Honda C50 Shop Manual

44
3. ENGINE
3.8 CARBURETOR (550, 565)
'!], Jet needl
'§ Throttle valve bottom
~ P ilot
outlet
~A i < '""~cc~cc-
_ _
@ Air screw outside
R\
I];
Bleed hoi
@ Needle jet
@ Slow·
(iJ)
Main jet
@
Croke valve
Main bore
Venturi sec tion ( l? m m: O.S7 inJ
\
S65
sso
___ ,4'
( 16~
' " ' "'
-~ -: _~#
@ Fuel passage
Air jet
1
Valve seat
1
Float valve
Figure 3-107. Carburetor cross sectional dia gram
1. AIR FLOW .
The air which passes t hrough the air cleaner enters
from inl et opening
(!),
passes under throttle va lve
@
(mai n bor e @l a nd taken into the inlet side of t he
engine. The power output is determi ned by the volume
of air ta ken into the engi ne. This necessary air flow
is contro ll ed by th e vertical movement o f the throttle
valve which varies the a rea of the main bore
@ .
(Fig.
3-1
07)
2. FUEL FLOW
The air which flow through the mai n bore
®
creates a low pressure directly under the th- r ottle
valve. It is here that the fuel o utlets f o r both the
main and slow systems are located. (Fig.
3-1
07)
a. Main System
The fuel passes through main jet
@
and enters the
needle jet holder
@.
The fuel mix es with the air.
taken in at air jet
@
and b led through air bleed hole
@ .
The fuel ai r mixture passes between needle jet
@
and jet needl e
@,
and dischargJs in a spray below
the throttle valve
@.
Th e fuel is atomi zed and mixed
with the main air stream ond is token i nto the
enr;~ine.
(Fi~.
3-1
07).