The Mallory Unilite Distributor 576 is designed for use with 1952-1970 Harley-Davidson Sportster motorcycles, and is also compatible with 1930-1973 Flathead (45 and UL) models. Installation requires a distributor clamp, either original or aftermarket. The Unilite module necessitates a 12-volt electrical system, operating within a voltage range of 7-16 volts, and should not exceed 16 volts. This document details installation instructions and important considerations for utilizing this distributor.
Distributor Components and System Requirements
The Mallory Unilite Distributor 576 comprises several key components, as illustrated in Figure A (referenced in all provided documents). These include the housing, adapter ring, standoff, screw, sleeve nut, shaft, set screw, cover, Unilite plate assembly, shutter wheel, grommet, pin, YH advance, O-ring, gear, roll pin, washer, and connector.
Successful operation of the Unilite distributor requires a compatible electrical system. Specifically, the Unilite module requires 7-16 volts DC. Therefore, a 12-volt electrical system is mandatory for installation. The documentation specifies that any coil, or combination of coils, with a total primary resistance of at least 2.0 ohms can be used. Recommendations include a 2-3 ohm coil for racing applications and a 3-4 ohm coil for street use. Coils with 4-5 ohms resistance are also permissible.
Installation Procedure
The installation process involves several steps, beginning with preparation and culminating in the installation of the distributor itself.
Step 1 involves positioning the engine. With the original point distributor still in place and correctly timed, the engine should be rotated until the points begin to open on the front cylinder lobe. The front cylinder lobe is identified as the narrower of the two lobes. If the point distributor is not already installed, the engine should be rotated to the beginning of the compression stroke. The timing hole should then be located, and the engine rotated until the advance mark is visible through the timing hole.
Step 2 requires disconnecting the electrical system. The ground cable from the battery must be removed, as well as the point wire at the coil. Following this, the original point distributor can be removed.
Electrical Considerations and Spark Plug Gap
Proper electrical configuration is crucial for optimal performance. The documentation emphasizes the importance of verifying that the electrical system does not exceed 16 volts.
Spark plug gap settings are dependent on the coil resistance used. A spark plug gap of .040" is recommended when using a 2-3 ohm coil. When utilizing a 3-4 ohm coil, a gap of .030" is advised.
Optional Advance Curve Adjustment
An optional spring kit (Part Number 29014) is available for the Unilite Distributor 576. This kit allows for customization of the advance curve, offering a choice of 14 different settings. The documentation does not provide details on the specific effects of each setting, only that the kit provides a wider range of adjustability.
Technical Support and Further Information
Mallory Technical Support is available at (775) 882-6600. Additional information can be found on the Mallory website at www.mrgasket.com.
Conclusion
The Mallory Unilite Distributor 576 provides an alternative ignition system for specific Harley-Davidson motorcycles. Successful installation requires adherence to the provided instructions, including ensuring a compatible 12-volt electrical system and appropriate spark plug gap settings. The optional spring kit allows for fine-tuning of the ignition advance curve. Users should consult the provided contact information for technical support and further details.