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Mosfet Regulator Rectifier for Harley Davidson Roadster Sportster 1984-1990

Mosfet Regulator Rectifier for Harley Davidson Roadster Sportster 1984-1990

SKU:RMS020-102638

Regular price £111.30 GBP
Regular price £133.56 GBP Sale price £111.30 GBP
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Mosfet Voltage Regulator - RMS020-102638

Harley Davidson Roadster XLS and Sportster XLH / XLX / 883 / 1000 / 1100 / 1200 - 1984-1990

A brand new Mosfet voltage rectifier regulator for the 1984-1990 Harley Davidson Sportster and Roadster range, supplied as a direct replacement for the original diode-style unit. MOSFET switching runs cooler than any OEM diode regulator, and the unit carries overheat protection - rather than burning up it simply switches off for a while and cools down, then resumes.

Beyond running cooler, the MOSFET design regulates by switching the stator coils rather than dumping surplus energy as heat. That reduces drag on the stator, giving fuel savings, steadier regulated power delivery, longer battery life, more usable engine power and better optimised charging. The regulator is plug-and-play with an improved heat sink, higher grade electrical components and a build quality above the original equipment. All products shipped are tested.

Key Features

  • MOSFET design - runs cooler than all OEM diode style regulators
  • Overheat protection: switches off to cool rather than burning out
  • Direct replacement, plug-and-play installation
  • Improved heat sink and charging capability
  • Higher grade electrical components, quality exceeding OEM equipment
  • Reduced stator load for fuel savings and longer battery life
  • Regulates by stator coil switching for optimised power delivery
  • All products shipped are tested

Technical Specs

Specification Detail
Width 68 mm
Length 94 mm
Height 34 mm
Fixation holes (centre to centre) 80 mm
Wire lengths 760 mm and 1370 mm
Number of plugs 1
Number of pins 2
Number of wires 3
Minimum charging voltage 14.5 V +/- 0.5 V
Maximum charging current 50 A / 500 W
Open circuit voltage Less than 15 V
Operating temperature -20 to 85 degrees Celsius

Vehicle Fitment Guide

Make & Model Years
Harley Davidson Roadster XLS 1984-1990
Harley Davidson Sportster XLH 1984-1990
Harley Davidson Sportster XLX 1984-1990
Harley Davidson Sportster 883 1984-1990
Harley Davidson Sportster 1000 1984-1990
Harley Davidson Sportster 1100 1984-1990
Harley Davidson Sportster 1200 1984-1990

OEM Part Number Cross Reference

Aftermarket replacement. OEM part numbers are listed for reference only.

Part Number Manufacturer / Brand
74523-84 Harley Davidson
74523-84A Harley Davidson
74523-84T Harley Davidson

Frequently Asked Questions

Does this regulator need modification to fit?

No. It is a plug-and-play direct replacement, with 3 wires on a single 2-pin plug and 80 mm mounting hole spacing to match the original unit.

What is included?

The complete MOSFET regulator rectifier unit with its leads, ready to install. No further components are supplied.

How can I tell whether my old regulator has failed?

With a fully charged battery and the engine running, measure at the battery terminals. A working system holds about 14.5 V plus or minus 0.5 V. No rise above resting voltage, or a climb well past 15 V, indicates a failed regulator. Battery condition is critical here - no voltage regulator can work correctly with a weak or faulty battery, so always fully charge the battery before testing the charging system or replacing parts.

What does MOSFET change compared with the original?

A diode-style regulator sheds surplus energy as heat, which is why the originals cook themselves. The MOSFET unit switches the stator coils instead, so it runs cooler, loads the stator less and cuts out temporarily on overheat instead of destroying itself.

Dispatched from the UK · 12-month warranty · Fitment support from our technical team
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Shipping calculated at checkout. Free shipping over £150. Terms apply