6-13
PERIODIC MAINTENANCE AND MINOR REPAIR
1
2
3
4
5
6
7
8
9
3. Check the engine idling speed
and, if necessary, adjust it to
specification by turning the throt-
tle stop screw. To increase the
engine idling speed, turn the
screw in direction
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.
Engine idling speed:
1,250–1,350 r/min
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 lubrica-
tion 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 occa-
sionally revving it to 4,000–5,000
r/min.
NOTE:
The engine is warm when it quickly
responds to the throttle.
a
b
1
1.
Throttle stop screw
EAU00629
Adjusting the carburetor
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
necessary professional knowledge
and experience. The adjustment
described in the following section,
however, may be serviced by the
owner as part of routine mainte-
nance.
EC000094
c
C
The carburetor has 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.
4PX-9-26-6(AUS) 7/25/00 5:27 PM Page 14
