Inspection Of Carburetor Components - Ducati 900SS Workshop Manual

-
-
CARBURETOR
Inspection of carbure tor components.
Todoy's intricate carburetors must
be
carefully inspected before reassembly to ensure
proper operation . The small passages in the carburetor body must be clear of any
foreign matter, and the body itself must be inspected lor wear ond damage.
A close inspechon must also be done on a ll componen t ports. Remember, by
understanding the opcro llon o f a carburetor. during your initial diagnosis. you w rll be
able to precisely prnpornt which circurt rs causing the problem.
FLOAT-VALVE ASSFMBLY: Check for dirt in the assembly, and wear on the flool-volve
needle w here it contacts the floot·volve seal.
SLIDE AND SLIDE BORE O F THE C ARBUR ETOR BODY: C heck the side of the slide for
Iorge scratches and w ear C heck the slide bore of the carburetor body for damage and
wear
PllOl SCREW: Check prlot·screw toper lor damage from its berng overtighten<.'Cl
Replace the screw if rl is damaged
FLOAT ASSEMBL Y. C heck the float assembly lor d amage that would rend er it
inoperable.
JET NEEDLE : Check the needle for wear marks or bends. Either condition warrants
replacement.
NEEDLE JET: Because it rs diflrculllo check a needle jet for wear, w e must assume that,
if the jet needle is w orn , the needle jet is a lso worn . Both must then be repla ced.
DIAPHRAGM AND ACCELERATOR-PUMP CARBURETORS: Diaphragms must be
checked for tears. crocks, holes. or other damage.
GASKETS: Gaskets should be replaced whenever the carburetor rs disassembled
O ·RIN GS All O ·rr ngs
u1
the carburetor should be checked for damage tha t could cause
o leak.
MAIN JET : C heck the morn jet for any type
of
blockage.
PILOT JET : Check rhe ptlot jet carefully for blockage. When replacing the piloljel, make
sure the correct type of pilot jet rs used. otherwise poor performance w ill result
AIR JET CIRCUITS C heck the a ir tel c rrcur ts lor b lockage.
TIPS:
On some carbureto rs tt
IS
r ossrble to physically interchange the pilot and main air jets.
II this is done, a very rich cond•hon at idle. and leaner·than·normol condition at midrange
and high speed. will occur
Do
notmterchonge the pilot and main air jets
STARTING·ENRICIICNCR PLUNGER· C heck the p lunger lor wear along the sides
Check the rubber seal on the bo11orn for w ear and da mage
. . . NOTE: The narrow nozzle in the joint must
be
connected to the small vacuum
. . . . line coming from the mixture control valve.
l his sharp rise in the vacuum octrvates the vacuum chamber in the rr••xture control valve.
The vacuum in this chamber pulls o valve in the fresh-air chamber off its seat. This allows
fresh air Ia pass rnto the intake tract by way ol the fresh-air line. The additional a ir leans
out the rich o ir·fucl mixture: entering tht! combustion chamber. This causes o beller burn
o f the a ir /fuel mixtur e. and very ltttle unburned gas will enter the e..:housl syslern .
GJDon> o9'1d o•eo
n)
noo:·vo:ve
needll'
nl)rl·.xr,o,-,~r
0 .57