Operation - Yamaha VMX12H Supplementary Service Manual

IGNITION SYSTEM
7-27
I
DE SC PTI ON
This model is equipped with a battery operated,
fu transistorized, breakerless ignition system.
By using magnetic pickup coils, the need for
contact breaker points is eliminated. This adds
to the dependability of the system by eliminating
frequent cleaning and adjustment of points
and ignition timing. The TCI (Transistor Control
Ignition) unit incorporates an automatic ad-
vance circuit controlled by signals generated by
the pickup coil. This adds to the dependability
of the system by eliminating the mechanical
advancer. This TCI system consists of two units;
a pickup unit and an ignitor unit.
Pressure sensor
Pickup coil
Ignitor unit
Advance control
Electronic advance circuit
Ignition coil x
Spark plug x 4
Battery

OPERATION

TCI Unit
The TCI functions on the same principle as a
conventional DC ignition system with the
exception of using magnetic pickup coils and a
transistor control box
breaker points.
TCI unit
Pickup Unit
The pickup unit consists of two pickup coils
and a flywheel mounted onto the crankshaft.
When the projection on the flywheel passes
pickup coil, a signal is generated and transmitted
to the ignitor unit. The width of the projection
on the flywheel determines the ignition advance.
The pickup coils are located in the right crank-
case cover.
in place of contact
a