Table of Contents
Advertisement
(12)Check the metering needles on the ends of main
adjuster screw and pilot screw.
If any needle is
damaged, the needle seat is considered to be
scratched.
Replace the carburetor body.
(13) Check the idle discharge hole and partial discharge
hole for clogging.
If clogged, clean with compressed
air.
Never use a wire.
(14) Check the main nozzle for clogging, and if necessary,
blow with compressed air.
(15)
Check the main adjuster link
shaft.
If the shaft
is
bent. replace.
(16)
If the main adjuster screw O-ring is swollen,
scratched, or broken, replace the O-ring.
2-5-9,
Assembly (GPX433F)
Reverse the procedure for disassembly,
Note
:
D
The assembly operation should be performed with
the main diaphragm completely in the groove in
pump body 2.
D
Take care so that the main diaphragm is installed in
the correct position.
Fit the rubber around the
check valve rim into the pump body groove.
D
The throttle mechanism should not be disassembled.
D
When assembling
,
be careful not to reverse the posi-
t ion of gaskets.
Carburetor failures are often ca used
by dust and incorrect service.
D
Install pump body 3 and pump body 4 together, and
tighten the bolts in a crosswise pattern.
2-5-10.
Installation (GPX433F)
For
installation,
reverse the procedure for removal.
No tightening torque for carburetor mounting nuts can be
specified for reason of its construction, and therefore,
they should be carefully tightened with a wrench
.
2-5-11.
Adjustments (GP X433F)
(1) The carburetor is properly adjusted and subjected to
a stringent test at the factory, and therefore, it
should not be disassembled or adjusted unnecessari-
'
Iy.
However, according to operating conditions or geo-
graphical conditions (weather, altitude. etc .). it may
require readjustment, cleaning and inspection.
In
this case the following parts must be readjusted.
1) Adjusting screw to control the pressure (fuel level) in
the regulator cha mber.
2) The pilot screw to control the mixture when the en-
gine idles.
3) The throttle stop screw to control the
idling
speed.
4) The main adjuster screw to control the mixture when
throttle opening is larger.
-
21-
ENGINE·
Carburetor
5) Slow jet and partial jet to control the mixture
in
the
range
from
ilding to medium speeds for smooth ac-
celeration.
Note:
As the throttle opening
increases,
the pilot screw,
slow jet and partial jet functions,
in
that order.
For details, refer to the carburetor manual.
(2) Adjusting the regulator chamber internal pressure
(fuel
level)
The performance of the diaphragm type carburetor
depends greatly on the condition of the regulator,
and therefore, the regulator must be adjusted very
carefully.
To adjust, first remove the fuel level pipe cap, and
run the engine at idling speed so that the fuel moves
up into the fuel level pipe.
Adjust the fuel level as
specified with the adjusting screw (located
in
the
carburetor bottom).
The fuel level must be maintained at the mating
sur-
face of the pump body with the carburetor body.
Turning in the adjusting screw raises the fue
l
level.
while turning out lowers the fuel level.
After the
adjustment. be sure to tighten the lock nut.
Fuel level and allowable difference
in
fuel level
:
+2 mm.
+ 5 _ 5 mm. (0 .28 in.)
2
1.
Fuel
level
pipe
2
.
Standard fuel level
Fig. 2-37
1.
Lock nut
2.
Adjusting screw
Fig. 2-38
Advertisement
Table of Contents
