40 ÷ 50 cm
- Connect the tester thermometer to the sump, us-
ing a cover with oil expressly prepared for probes.
- Start the engine and before adjusting the idle
speed, make sure that the oil temperature is be-
tween 70÷80 °C.
Specific tooling
020331Y Digital multimeter
- Using the rpm indicator in the analyser or a sep-
arate one, adjust the idle screw.
N.B.
THE WASTED SPARK IGNITION SYSTEM OFFERS RE-
MARKABLE POWER. READINGS MAY NOT BE ACCU-
RATE IF INADEQUATE RPM INDICATORS ARE USED.
Specific tooling
020332Y Digital rpm indicator
Characteristic
Idle speed
about 1900/2000 rpm
- Adjust the flow screw until a percentage of carbon
monoxide (CO) is obtained. When the screw is
loosened the CO value rises (rich mix). Tightening
the screw decreases the CO (lean mix).
- If the adjustment of the flow screw causes a rpm
increase readjust the revs again and if necessary,
the flow screw to reach stable values.
Characteristic
CO adjustment
3,2% ± 0,5
- When the oil temperature, the numbers of revs and the percentage of carbon monoxide are respected
the idle carburetion is considered correct.
- Further information can be drawn from the analyser:
- carbon dioxide percentages (CO2), the percentage of carbon dioxide has an inverted course compared
to the percentage of (CO), values over 13% are considered correct.
- Non complying values indicate lack of tightness in the exhaust system.
- Unburned hydrocarbons (HC) are measured in parts per million (PPM). The HC value decreases while
the rpm increases; with the engine at idle it is normal to obtain 200 ÷ 400 PPM, these emission values
are deemed normal for an engine with a diagram of timing for motorcycles. Higher values can cause
Engine MSS ZIP 100 4T
ENG - 126
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