Electric Starter System; General; Wiring Diagrams; Start Relay - Buell 2008 XB SERIES Electrical Diagnostics Manual

ELECTRIC STARTER SYSTEM

GENERAL

The starter is made up of an armature, field winding assembly,
solenoid, drive assembly, idler gear and drive housing. The
starter motor torque is increased through gear reduction. The
gear reduction consists of the drive pinion on the armature, an
idler gear and a clutch gear in the drive housing. The idler gear
is supported by rollers. The clutch gear is part of the overrun-
ning clutch/drive assembly. The overrunning clutch is the part
which engages and drives the clutch ring gear. It also prevents
the starter from overrunning. The field windings are connected
in series with the armature through brushes and commutator
segments.

Wiring Diagrams

For additional information concerning the starting system circuit,
see the wiring diagrams in this section and Section 2, Engine
Management.

Start Relay

The start relay is not repairable. Replace the unit if it fails.

Starter Interlock

See Section 2, Engine Management, for operation and
troubleshooting information.
1-2 2008 Buell XB Diagnostics: Starting / Charging

OPERATION

See Figure 1-1. When the starter switch is pushed, the starter
relay is activated and battery current flows into the pull-in
winding (10) and the hold-in winding (11), to ground. The
magnetic forces of the pull-in and hold-in windings in the
solenoid push the plunger (7) causing it to shift to the left. This
action engages the pinion gear (1) with the clutch ring gear
(13). At the same time, the main solenoid contacts (8) are
closed, so battery current flows directly through the field wind-
ings (3) to the armature (4) and to ground. Simultaneously, the
pull-in winding (10) is shorted. The current continues flowing
through the hold-in winding (11) keeping the main solenoid
contacts (8) closed. At this point, the starter begins to crank
the engine. After the engine has started, the pinion gear (1)
turns freely on the pinion shaft through the action of the over-
running clutch (12). The overrunning clutch prevents the clutch
ring gear (13) (which is now rotating under power from the
engine) from turning the armature (4) too fast. When the starter
switch is released, the current of the hold-in winding (11) is fed
through the main solenoid contacts (8) and the direction of the
current in the pull-in winding (10) is reversed. The solenoid
plunger (7) is returned to its original position by the return
spring, which causes the pinion gear (1) to disengage from the
clutch ring gear (13).
1.2