Yamaha Virago XV535, Owner'S Manual

Page: 50 / 96

PERIODIC MAINTENANCE AND MINOR REPAIR
6-13
6
EAU00630
Adjusting the carburetors
The carburetors are important parts of
the engine and require very sophisti-
cated adjustment. Therefore, most car-
buretor adjustments should be left to a
Yamaha dealer, who has the neces-
sary professional knowledge and expe-
rience. The adjustment described in
the following section, however, may be
serviced by the owner as part of routine
maintenance.
EC000095
CAUTION:
@
The carburetors have been set and
extensively tested at the Yamaha
factory. Changing these settings
without sufficient technical knowl-
edge may result in poor perfor-
mance of or damage to the engine.
@
EAU01168
Adjusting the engine idling
speed
The engine idling speed must be
checked and, if necessary, adjusted as
follows at the intervals specified in the
periodic maintenance and lubrication
chart.
NOTE:
@
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 1,000–
2,000 r/min while occasionally rev-
ving it to 4,000–5,000 r/min.
NOTE:
@
The engine is warm when it quickly re-
sponds to the throttle.
@
3. Check the engine idling speed
and, if necessary, adjust it to spec-
ification by turning the throttle stop
screw. To increase the engine
idling speed, turn the screw in di-
rection
a
. To decrease the engine
idling speed, turn the screw in
direction
b
.
NOTE:
@
If the specified idling speed cannot be
obtained as described above, have a
Yamaha dealer make the adjustment.
@
1. Throttle stop screw
Engine idling speed:
1,150–1,250 r/min
E_3bt.book Page 13 Thursday, September 7, 2000 10:01 AM