PIAGGIO 500 cc Service Manual page 209

To increase CO it is necessary to increase fuel injection timing.
To decrease CO it is necessary to decrease fuel injection timing.
Regulate the trimmer value according to indications given in the table:
NOTE: A trimmer value of 0 corresponds to medium fuel injection.
After regulation, engines may find carburation with either positive or negative trimmer values. This is due to normal
production tolerance.
After varying the trimmer value,
wait for the CO to adjust itself.
When regulation is shown to be correct, press OK
to memorize the value in the control unit.
Select the menu to "PARAMETERS" and "ECU
INFORMATION" to receive confirmation that the
new trimmer variation has been memorized.
NOTE: When the CO percentage is correct and the CO
will also be false.
In this case check accurately the exhaust system seal.
TRIMMER
FUEL INJECTION TIMING
VALUE
+100
HIGH
⇑
+ 50
+ 10
0 MEDIUM
- 10
⇓
- 50
-100 LOW
value does not fall within the preset values, LAMBDA value
2
C O
INCREASES
⇑
⇓
DECREASES
Fuel injection
9
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