Ignition System; Description; Operation; Sidestand Relay Operation - Yamaha XZ550RJ 1982 Service Manual

Description

This model is equipped with a battery operated,
fully transistorized, breakerless ignition system. By
using magnetic pickup coils, the need for contact
breaker points is eliminated. This adds to the de-
pendability of the system by eliminating frequent
cleaning and adjustment of points and ignition tim-
ing. The TCI (Transistor Control Ignition) unit incor-
porates an automatic advance 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.
NOTE:
The ignition circuit can be operated only when the
sidestand is up (the sidestand switch is on) or the
transmission is in neutral.

Operation

The TCI functions on the same principle as a con-
ventional DC ignition system with the exception of
using magnetic pickup coils and a transistor control
box (TCI) in place of contact breaker points.
1. Pickup unit
The pickup unit consists of two pickup coils
and a flywheel mounted onto the crank-
shaft. When the projection on the flywheel
passes a pickup coil, a signal is generated
and transmitted to the ignitor unit. The width
of the projection on the flywheel determines
the ignition advance.
1. Pickup coils
2. Ignitor unit
This unit controls wave form, duty con-
trol, switching, electronic ignition ad-
vance, etc. The duty control circuit re-
duces electrical consumption by con-
trolling the duration of the primary igni-
tion current.
The ignitor unit also has a protective cir-
cuit for the ignition coil. If the ignition
switch is on and the crankshaft is not
turning, the protective circuit interrupts
the current flow to the primary coil after
a few seconds. When the crankshaft is
turning, however, the ignitor unit sends
current to the primary coil.
1. TCI Unit

Sidestand relay operation

The sidestand relay operates by shorting the
TCI control current. When the sidestand is
down, the sidestand relay is closed, and the
TCI control current is grounded through the
sidestand relay. Thus, the engine will not run
with the sidestand down unless the transmis-
sion is in neutral.
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