Harddrive Regulator - Chrome XL `1978-1981 OEM 74504-78 — Harley-Davidson Sportster 1000, 1000 Roadster (1980-1981)

Harddrive chrome voltage regulator for Harley-Davidson Sportster XL models 1978–1981, meeting or exceeding OEM 74504-78 specifications. Built with high-power SCR technology and sealed encapsulation for cooler, more reliable operation in heat-prone applications.

Features

• Meets or exceeds OEM specifications
• High-power SCR (Silicon Controlled Rectifier) for cooler operation
• Sealed, high-temperature encapsulation
• Surface-mount circuit board minimizes thermal impedance
• OEM-grade wiring harness

Specifications

• Brand: Harddrive
• Manufacturer Part #: H0478C
• UPC: 191361170270
• OEM Reference: 74504-78
• Length: 4.68 in
• Width: 3.5 in
• Height: 1.68 in
• Weight: 0.8 lbs
• Country of Origin: China (Mainland)

Fitment

Fits Harley-Davidson Sportster XL models 1978–1981. Direct replacement for OEM Harley part number 74504-78.

Frequently Asked Questions

Will this fit my 1982+ Sportster?

No — this regulator is specific to 1978–1981 XL models. Later Sportsters use different charging systems.

What does the regulator do?

It controls the alternator output voltage to keep your battery charged without overcharging. A failed regulator will leave you stranded or damage electrical components.

Is this the same as the original Harley part?

This Harddrive regulator meets or exceeds OEM 74504-78 specifications and is a direct replacement for the original.

What makes this regulator run cooler?

The high-power SCR technology and sealed heat-dissipating encapsulation allow the regulator to operate at lower temperatures than standard designs, improving reliability.