Scorpa SY-250FR 2008 Manual Manual page 31

Effects of the setting parts on the throttle valve opening
Fully open
Closed
Pilot system
The FLATCR carburettor is manufactured with a pilot screw. The pilot screw adjustment rangdes from
fully closed throttle (don‟t tighten) to 3 turn open throttle.
Maint jet
Main jet adjustment
The richness of the air-fuel mixture at full throttle can be set by changing the main jet.
If the air-fuel mixture is too rich or too lean, the engine power will drop, resulting in poor acceleration.
Main screw adjustment
The richness of the air-fuel mixture with the throttle fully closed to ¼ open can be set by turning the
main screw. Turning in the main screw will make the mixture lean at low speeds, and turning it out will
enrich it.
NOTE :
If the engine idling speed fluctuates, turn the main screw only ½ of a turn in either direction.
Pilot jet adjustment
27
Valve throttle
1
3/4
1/2
1/4
0
Jet needle
Main screw
Pilot screw
Jet needle hole
Pilot jet