Carburetor Tuning Or Adjustment Procedure - Vento Phantom R4i Service Maintenance Manual

CARBURETOR TUNING OR ADJUSTMENT PROCEDURE

After installation the carburetor in the engine as per above said procedure, follow the following steps:
1. Warming up the engine to the normal running temperature.
2. Adjust Idling speed to 1400 RPM by throttle stop (Idle) screw.
3. Turn the airscrew all the way inside until seats lightly in the carburetor body.
1. If engine stops then... OK (Incase does not stop, check for air leakage from insulator "O" ring and rectify).
2. Readjust air screw position to ¾ turns out.
3. Start the engine and increase the Idling speed by turning the Idle (stop) screw in anticlockwise direction, till the
engine speed increases to the range of 2000 to 2500 RPM.
4. Open the air screw outwards (anticlockwise) slowly till engine RPM increases to the peak/highest speed
position while setting. Now stop adjusting air screw (Maximum recommended air screw opening position 1¾
turns out).
5. Readjust Idling speed to 1400±100 RPM by the throttle stop screw & ensure that exhaust emission Carbon
Monoxide CO % 1.5 to 2.0 %.
6. After adjusting Idling speed, check for its stability/flat spot/missing if any, by accelerating few times. Repeat
above said steps until engine speed increases smoothly.
NOTE:
Do not apply force or over tight the air screw. Damage may occur incase the air screw is being tightened
•
against the air screw seat.
Incase the Idling speed is too low engine will stop; if it is too high will cause fuel consumption.
•
WARNING
While running engine in Idling speed turn the handle bar to the extreme left or right hand side, if any change in
idling speed noticed, the accelerator cable may be wrongly routed or improperly adjusted. Correct the same before
test ride.
VENTO MOTORCYCLES
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