Chopper Cache

Fitment, source notes & wire connections

1978 Honda CB750 Four Field Charging System

1978 · CB750 Four · Field-excited alternator / separate rectifier and field regulator

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Community reference trace · By Choppercache

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Diagram reference

An interactive charging-system reference for a 1978 Honda CB750 Four using its field-excited alternator architecture rather than a permanent-magnet template.

This diagram shows 6 components and 11 wire connections. The details below describe the saved diagram; they do not confirm compatibility with your machine.

Recorded fitment
1978 CB750 Four
Configuration
Field-excited alternator / separate rectifier and field regulator
Circuits labeled in the diagram
Charging, Main, Grounds

Components shown

  • ALT · Field-Excited Alternator

    3 AC outputs / rotor field pair

  • RECT · Three-Phase Rectifier

    3 AC in / DC out / ground

  • BAT · Battery

    Negative grounded to frame

  • GND · Ground

    Battery negative return

  • KEY · Key Switch

    Battery / accessory / ignition-on / spring start

  • REG · Field Regulator

    System sense / rotor-field control / ground

Source notes

Community reference trace · Choppercache Community troubleshooting references identify three stator-phase leads, a separately excited rotor field, and grounded rectifier/regulator paths. Confirm connector colors and replacement-part pinouts on the exact motorcycle. Recorded reference URLs: https://forum.chopcult.com/forum/nbsp/japanese-bikes-build-threads/50471-1978-cb750-bobber-need-help-simple-wiring-diagram-trouble-shoot https://www.cb750.com/threads/alternator-throwing-0-volts-on-1978-cb750k.3653/

Community reference trace · Choppercache

Publication note: Community troubleshooting references identify three stator-phase leads, a separately excited rotor field, and grounded rectifier/regulator paths. Confirm connector colors and replacement-part pinouts on the exact motorcycle.

Limitations and checks

Community troubleshooting references identify three stator-phase leads, a separately excited rotor field, and grounded rectifier/regulator paths. Confirm connector colors and replacement-part pinouts on the exact motorcycle. 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 (11)
Wire connections recorded in this diagram
FromToGaugeColor
BAT · B−GND · GND6 AWGBlack / frame ground
BAT · B+KEY · BATReference not shownDiagram red / source unlabeled
ALT · AC 1RECT · AC 1Reference not shownDiagram green / source unlabeled
RECT · DC +BAT · B+Reference not shownDiagram green / source unlabeled
ALT · AC 2RECT · AC 2Reference not shownDiagram green / source unlabeled
RECT · GNDGND · GND6 AWGBlack / frame ground
KEY · ONALT · FIELD +Reference not shownDiagram red / source unlabeled
ALT · AC 3RECT · AC 3Reference not shownDiagram green / source unlabeled
KEY · ONREG · SENSEReference not shownDiagram green / source unlabeled
ALT · FIELD −REG · FIELDReference not shownDiagram green / source unlabeled
REG · GNDGND · GND6 AWGBlack / frame ground
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What happened on real bikes?

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Community reference
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