Suzuki MT50 Service & Parts Manual page 169

9-25-2. Specifications
Main jet
Air jet . . . . . . . . . . . . . . . . . . . . .
Jet needle
Needle jet . . . . . . . . . . . . . . . . . . .
Throttle valve cutaway. . . . . . . . .
Pilot jet
Pilot outlet . . . . . . . . . . . . . . . . .
Pilot air adjusting screw ....... .
Needle valve seat ............ .
Starter jet
A. Th rattle valve :
The throttle valve determines the amount of
air sucked into the engine through the main
bore by cha�ing the throat opening, thus
control I ing engine output.
raised by turning the throttle grip inward, the
throat opening becomes larger and larger, per­
mitting a greater amount of air to flow under
it and resultantly increasing engine output.
The throttle valve has a cutaway which deter­
mines the velocity of air flow and the amount
of fuel to be primed up at medium speed
from � to % throat opening.
cutaway is 2.5 mm in size as indicated by the
cutaway size number.
throttle valve cutaway gives a leaner mixture
and a lower numbered one a richer mixture.
B.
Jet needle :
The j e t needle has five grooves at the upper
part and is tapered at the lower end approx­
imately from the center. I t is clipped into the
third groove as counted f rom the top and is
inserted in the center of the throttle valve. The
tapered end is inserted into the needle jet. En­
gine output i s regulated by the amount of air
inhaled into the engine, as explained in para­
graph A. When the amount of air inhaled into
the engine is changed, the amount of fuel mix­
ed wi t h the air must be changed as well to
keep the fuel/air mixture ratio proper at all
times. The clearance between the jet needle
and the needle jet determines the amount of
fuel which i s pumped up through the main jet
. . . . . . . . . . . . . . . . . .
.................
As the valve is
The standard
A higher numbered
� 1 0 5
2.0 mm ¢>
3 G9, clipped into 3 rd groove
E-0
� 2.5 (2 .5 mm)
� 17.5
.
.
0.9 mm¢
1 � turns back open
1.2
mm
�40
Fig. 9-25-2 Throttle valve
Fig. 9-2 5-3 Cutaway size number
Fig. 9-25-4 Jet needle and clip
67