Pcv (Positive Crankcase Ventilation) (After '05 Model) - Honda 2003 NPS50 Ruckus Service Manual

TECHNICAL FEATURES

PCV (Positive Crankcase Ventilation) (After '05 model)

This system ventilates the crankcase b y injecting fresh air. Properly ventilating t h e crankcase prevents t h e stagnant blow­
by gas that contains gasoline o r water vapor from contaminating the engine oil under the driving conditions that result in
low engine oil temperature.
The PCV system consists of the air cleaner, PCV control solenoid valve and PCV reed valve.
The PCV reed valve prevents the back-flow of blow-by gas to the air cleaner case. The solenoid valve maintains consistent
engine idle speed by controlling the crankcase air flow depending on throttle opening and engine speed.
1 . The ECM signals the solenoid valve to choke airflow to maintain a ,--- -- -- -- -- -- -- -- -- -,
sta ble idle speed.
2. When throttle opening and engine speed increase, the ECM signals
the solenoid valve to open and ventilate crankcase.
2-2
AIR CLEANER
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2000 3000 3300
F'
IDLE
PCV REED VALVE
FRESH AIR
BLO W-BY GAS
6700 6800
ENGINE SPEED (rpm)