PERIODIC MAINTENANCE AND ADJUSTMENT
7-14
7
EAU39931
A
d
justin
g
the car
b
uretor
The carburetor is an important part of
the engine and requires very sophisti-
cated adjustment. Therefore, most
carburetor adjustments should be left
to a Yamaha dealer, who has the nec-
essary professional knowledge and ex-
perience. The adjustment described in
the following section, however, may be
serviced by the owner as part of rou-
tine maintenance.
NOTICE
ECA10551
The car
b
uretor has
b
een set an
d
ex-
tensively teste
d
at the Yamaha fac-
tory. Chan
g
in
g
these settin
g
s
without sufficient technical knowl-
e
dg
e may result in poor perfor-
mance of or
d
ama
g
e to the en
g
ine.
EAU21363
A
d
justin
g
the en
g
ine i
d
lin
g
spee
d
The engine idling speed must be
checked and, if necessary, adjusted as
follows at the intervals specified in the
periodic maintenance and lubrication
chart.
TIP
A diagnostic tachometer is needed to
make this adjustment.
1. Attach the tachometer to the
spark plug lead.
2. Start the engine and warm it up for
several minutes at 1000–2000
r/min while occasionally revving it
to 4000–5000 r/min.
TIP
The engine is warm when it quickly re-
sponds to the throttle.
3. Check the engine idling speed
and, if necessary, adjust it to
specification by turning the throt-
tle stop screw. To increase the en-
gine idling speed, turn the screw in
direction (a). To decrease the en-
gine idling speed, turn the screw in
direction (b).
TIP
If the specified idling speed cannot be
obtained as described above, have a
Yamaha dealer make the adjustment.
1. Throttle stop screw
En
g
ine i
d
lin
g
spee
d
:
1600–1800 r/min
(a)
(b)
1
UB5180E0.book Page 14 Monday, June 9, 2014 1:20 PM
