I
No
pape
r reaction
I
I Replace
MCV
I
OK
Inspect vacuum lines
Assembly 1
and
3
way
j
oont
ins
tollato
on
Damag
e
I
Repla
ce
vacu
um
lin
es
I
Incorrect rou
ti
ng
I
Rout
e correctly
II
Co
nt
oo
l volve
2)
Coobu
oe
tor
3)
Connisl
et
4)
Fuel
tonk
0.62
I
CARBURETOR
Mixture
co
n
trol
valve troubleshooting.
l
)R
emove
th
e
Mi
xture
Con
lroiVolv
e
{M
C
V)
case
co
ver and st
or
t
th
e engin
e.
2)Pioce a piece
of
paper close to
the
in
take side
of
th
e
MCV
.
3
)Rev
the
engine
to
about 5000 rpm, and quic
kl
y close
the
throttle.
The
paper
should
be
drown
towards
the
MCV
intake.
Carburetor air
ve
nt
sys
tem
(C
alifornia-only
models
).
All
new
motorcycl
es
sold in California ore required to hove on emission
ca
nnister
in
the
vent lines running
from
the
fuel
tonk
and
carbureto
rs
. This
is
to prev
ent
th
e
di
scharging
of
fuel
vap
ors
int
o
the
atmosphe
re.
Troubl
eshooting
hints
.
1 )If it
is
diffic
ult
to
se
t or maintain carburetor synchroniza
ti
on,
and
th
e exhaust gas
analyzer shows a
leon condition exists even though
the
mixture screw has been
enr
ic
hed, check for on air leak
in
the
carburetor or intake manifold. Spray contact
cleaner on
the
supsect
ed
po
int,
and
watch the
CO
meter. If
CO
increases, you've
found
th
e air leak.
2)To check
foro
do
gger or restricted
low
-speed jet,
turn
the
mixture
sc
r
ew
out {
ri
cher)
one full
turn,
or more, and watch the
CO
needle. There should
be
o noticeable
increase
in
CO
.
If
there
is
not, the low
-s
peed jet is blocked.
3)A
common complaint
from
customers is
th
at
th
e bike h
esi
tates
or dies
wh
en
th
e t
hr
o
lf
le
is
opened.
Th
e carburetor circuits
th
at con
tr
ol engine speed from idle to midrange ore
called transit
io
n circuits. Transi
ti
on circui
ts
ore actually a
co
mbination of idle and
midrange circuits. A problem with either
th
e idle or midrange carburetor circuits or
on
ig
nit
io
n problem, con cause hesitation or missing dur
in
g transition.
4)1f
th
e exhaust gas analyzer readings show normal
CO
and normal
HC,
but the bike
still
hesitates off idle, adjust
th
e float levels on models with
CV
carburetors.
5)0n
those models with on accelerator pump, olf·
id
le hesitation con usually
be
traced
to on
improperly adjusted accelerator pump. Use the exhaust
ga
s
ana
lyzer to adjust
th
e
acc
elerator pump.
Raise
th
e engine speed to 5000 rpm, h
old
it there for
lw
o
second
s,
and watch
th
e
CO
and
HC met
ers
. If
th
e
HC
needle
ri
ses
before the
CO
needle,
th
en a leon misfire has occurred.
Th
e accelerator
pum
p should be slig
ht
ly
enrichened (pump stroke increased
);
repeat
th
e t
es
t.
Continue to enrichen
the
accelerator pump
and
test
the
engine
un
til the
CO
and
HC
needles rise toge
the
r;
the
leon misfire will hove been eliminated.
Th
is
adju
stment will
yield
smooth, crisp
throHie
response.
COMM
ON
CAUSES OF CUST
OME
R COMPLA
IN
TS
l )Carburetors not properly synchronized
and
exhau
st
gas
analy
zer' d.
2)Exce
ss
ively
ri
ch or leon corburetion.
3)C
i
ogged
or r
es
tr
icted
int
e
rna
l
pa
ssages.
4)
St
icking
fl
oats.
5) Lea
ki
ng choke.
6)W
orn inte
rna
l ports
(jet
needle, needle jet,
fl
oa
t valve) .
7)
Di
rty or obstruc
ted
air cleaner.
8)A
ir leaks.
9)Mo
lfunctiontng
fuel
subsystem.
1 0)
Exhaust
sys
t
em
altered.
·-
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