Ignition Timing Control - Suzuki DF 25 Service Manual

IGNITION TIMING CONTROL

Outline
The ignition timing varies based upon engine speed.
The CKP sensors monitor current engine speed and send signals to the CDI unit.
Based on this signal, the CDI unit determines the optimum ignition timing and supplies voltage to the primary
winding of the ignition coil.
Basic sensor
CKP sensor :
Informs CDI unit of engine speed and crankshaft angle.
Control mode
When starting (at the time of cranking):
The ignition timing is fixed at BTDC 5° until the engine starts.
When operating (normal operation):
The ignition timing varies in the range of BTDC 5° – 31° (DF25) or 29° (DF30) according to the engine
operating condition.
ENGINE CONTROL 3-5
CDI unit
Ignition timing is deter-
mined by a digital map de-
signed in relation to engine
speed.
Signal Signal Signal
Ign.coil Ign.coil Ign.coil