Sym GTS 250, Service Manual

Page: 57 / 217

4. Fuel System
4-10
Adjustment of Idle Speed
Caution
y Air screw was set at factory, so no adjustment
is needed. Note the number of turns it takes to
screw it all the way in for ease of installation.
y The parking brake must be used to stop the
ATV to perform the adjustments.
Use a tachometer when adjusting engine RPM.
Screw in air adjustment screw gently, then back up
to standard turns.
Standard turns: 2 1/2 turns
Warm up engine; adjust the throttle stopper screw
of throttle valve to standard RPM.
Idle speed rpm: 1500 ± 100 rpm
Connect the hose of exhaust analyzer to exhaust
front end. Press test key on the analyzer.
Adjust the pilot screw and read CO reading on the
analyzer
CO standard value: 1.3~2.0 %
Accelerate in gradual increments; make sure rpm
and CO value are in standard value after engine
running in stable. If rpm and CO value fluctuated,
repeat the procedures described above for
adjusting to standard value.
To this chapter contents
Air adjustment screw
Throttle cable adjustment nuts
Throttle cable adjustment nuts