Table of Contents
This is an old revision of the document!
REF: Electrical System
Ironhead - Simplified Wiring Schematics
This wiring diagram is a minimal config - No Starter - No Turn Signals - No Front Brake Switch - No Kill Switch.
The ignition module is an Ultima Single-Fire version, feeding separate trigger signals to the dual coils to fire the front & rear spark plugs separately. It fits in the nosecone where previously only the cam sensor plate mounted. A dual-fire version of the Ultima ignition could be used instead, with the appropriate dual-fire coil. Using the VOES connection (which helps with idle & cruising spark timing by providing more advance) is recommended, but implementing a tachometer is optional.
There are only six wire colors to minimize wire purchase: Black - White - Red - Blue - Yellow - Green. There are enough colors so that no connecting point should have the same color twice in order to make it easier to know which device is connected to/from another device.
This circuit uses the Frame/Engine for ground conduction. Be sure you have good ground points at the needed locations or run a separate black wire to those locations to assure a good ground.
Beware that the brake light shares the same fuse as the ignition circuit - So, if you have a short to ground in the brake circuit it will blow the fuse & kill the ignition. You could add a separate fuse for the brake light to avoid that potential problem.
The diagram shows an optional Gen Light, implemented with a diode and an incandescent bulb.
To implement the VOES, add it with a vacuum hose to the carb - then wire the single VOES wire into the Violet Wire of the Ultima ignition module.
To implement a tachometer, use a normal HD dual-fire tach and wire the input signal to the Green Wire of the Ultima module.
Some Other Simplfied Wiring Diagrams to represent basic wiring:
Wiring for Magneto Fired Sportsters 1) |
Wiring for an Electric Start Sportster 2) |
Generic HD Wiring Diagram 3) |