Wiring diagrams /
1978 Harley Sportster XLH Two-Brush Generator
Fitment, source notes & wire connections
CHOPPERCACHE / WIRING REFERENCE
Gold = powered · moving dashes = current
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Choppercache original · By Choppercache
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Diagram reference
An interactive 1978 Harley-Davidson Sportster XLH chopper diagram using a two-brush generator and external regulator.
This diagram shows 14 components and 20 wire connections. The details below describe the saved diagram; they do not confirm compatibility with your machine.
Recorded fitment 1978 XLH
Configuration Chopper
Circuits labeled in the diagram Charging, Main, Grounds, Lighting, Ignition, Starting
Components shown
GEN · Two-Brush Generator Armature / field output
REG · External Generator Regulator BAT / A / F / ground
BAT · Battery Negative grounded to frame
GND · Ground Battery negative return
KEY · Key Switch Battery / accessory / ignition-on / spring start
DIMMER · Toggle Switch Two-position selector
HEAD · Headlight High / low beam
COIL · Ignition Coil Key-switched primary
DIST · Distributor Points trigger
BRAKE SW · Brake Switch Normally-open brake-light switch
BRAKE · Brake Light Tail / brake lamp
GND · Ground Brake-light chassis return
SR-791783-1 · Starter Relay Battery / start trigger / motor
M-799428-2 · Starter Motor High-current motor / case ground
Source notes
Choppercache original · Choppercache
Multi-wire generator and external regulator alternative for a 1978 XLH chopper.
No external source URL is recorded for this diagram.
Choppercache original · Choppercache
Publication note: Multi-wire generator and external regulator alternative for a 1978 XLH chopper.
Limitations and checks
Multi-wire generator and external regulator alternative for a 1978 XLH chopper. These recorded references do not establish that this circuit has been tested on your motorcycle. Match the installed components, polarity, terminal pinouts, wire sizes, and circuit protection to the relevant service documentation before applying power.
Verify your hardware pinouts, polarity, wire sizes, and component ratings before applying power.
Wire connections (20)
Wire connections recorded in this diagram
From To Gauge Color BAT · B− GND · GND 6 AWG Black / frame ground BAT · B+ KEY · BAT Reference not shown Diagram red / source unlabeled GEN · A REG · GEN Reference not shown Diagram green / source unlabeled REG · BAT BAT · B+ Reference not shown Diagram green / source unlabeled KEY · ACC DIMMER · IN Reference not shown Diagram yellow / source unlabeled DIMMER · HIGH HEAD · HIGH Reference not shown Diagram yellow / source unlabeled DIMMER · LOW HEAD · LOW Reference not shown Diagram blue / source unlabeled KEY · ON COIL · KEY Reference not shown Diagram brown / source unlabeled COIL · POINTS DIST · POINTS Reference not shown Diagram brown / source unlabeled KEY · ACC BRAKE SW · IN Reference not shown Reference not labeled BRAKE SW · OUT BRAKE · BRAKE Reference not shown Diagram red / source unlabeled BRAKE · GND GND · GND Reference not shown Black / frame ground KEY · ACC BRAKE · TAIL Reference not shown Diagram yellow / source unlabeled SR-791783-1 · 30 BAT BAT · B+ 6 AWG Red SR-791783-1 · 87 MOTOR M-799428-2 · MOTOR 6 AWG Red SR-791783-1 · 85 GND GND · GND 8 AWG Black KEY · START SR-791783-1 · 86 START Reference not shown Blue GEN · F REG · F Reference not shown Diagram green / source unlabeled GEN · CASE GND · GND 6 AWG Black / frame ground REG · GND GND · GND 6 AWG Black / frame ground