Adjusting The Carburetor; Adjusting The Engine Idling Speed - Yamaha TT-R TT250RN Owner's Manual

PERIODIC MAINTENANCE AND MINOR REPAIR

Adjusting the carburetor

The carburetor is an important part of
1
the engine and requires very sophisti-
cated adjustment. Therefore, most
carburetor adjustments should be left
2
to a Yamaha dealer, who has the
necessary professional knowledge
3
and experience.
described in the following section,
4
however, may be serviced by the
owner as part of routine mainte-
5
nance.
cC
6
The carburetor has been set and
7 extensively tested at the Yamaha
factory. Changing these settings
without sufficient technical knowl-
8
edge may result in poor perfor-
mance of or damage to the engine.
9
EAU00629
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.
The adjustment
NOTE:
A diagnostic tachometer is needed to
make this adjustment.
1. Attach the tachometer to the
EC000094
2. Start the engine and warm it up
NOTE:
The engine is warm when it quickly
responds to the throttle.
spark plug lead.
for several minutes
1,000–2,000 r/min while occa-
sionally revving it to 4,000–5,000
r/min.
6-13
EAU01168
b
1
1. Throttle stop screw
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
at
decrease the engine idling speed,
turn the screw in direction b.
Engine idling speed:
1,250–1,350 r/min
NOTE:
If the specified idling speed cannot
be obtained as described above,
have a Yamaha dealer make the
adjustment.
a
a.
direction To