Ignition System; Digital Ignition Control System Description - Yamaha VMX12H Supplementary Service Manual

SYSTEM
IGNITION

IGNITION SYSTEM

DIGITAL IGNITION CONTROL SYSTEM
DESCRIPTION
The electronic ignition that sparksthe engine
is computer controlled and operated by the
digital CPU (microprocessor). It has a pre-
programed ignition advance curve.
This programed advance curve closely
matches the spark timing to the engine's
ignition requirements. Only one pickup coil is
needed to meet the requirements of the digi-
tal ignitor unit.
The digital ignitor also includes the control
unit for the electric fuel pump.
Clutch switch
Side stand switch
Pressure sensor
Pick up coil
CPU (microprocessor)
Digital ignitor unit
Fuel pump
Fuel pump control relay
Ignition coil
OPERATION
The following operations are digitally-per-
formed by signal from the pickup coil signal:
1.Determing proper ignition timing.
2.Sensing the engine revolution speed.
3. Determing timing for switching on ignition
coil (duty control).
Increasing ignition coil primary current for
4.
starting the engine.
5.Sensing engine stall.
6. Preventing over-revolution
-18-
of
the engine.