Voltage Regulator for Aprilia, Derbi, Gilera, Malaguti, Piaggio and Vespa
SX 50, Derbi 50, RCR 50, F15, Zip 50 and LX 50, 1993-2020 - part number RMS020-103973
This is a brand new aftermarket voltage regulator rectifier covering a wide family of Italian and Spanish 50 cc scooters and mopeds built between 1993 and 2020, including the Aprilia SX 50, Derbi 50, Gilera RCR 50, Malaguti F15, Piaggio Zip 50 and Vespa LX 50. It is a direct replacement for your original unit and fits plug-and-play, so installation needs no assembly and no changes to the machine.
The regulator has a 68 mm by 60 mm footprint and stands 20 mm high, connecting through a single plug with five pins. Compared with the part it replaces it uses a higher grade of electric components and carries an improved heat sink, which also improves charging capability - heat is the usual reason a small scooter regulator gives up. Charging voltage is held at a minimum of 14.5 V plus or minus 0.5 V, the maximum charging current rating is 50 A or 500 W, open circuit voltage stays under 15 V, and the unit is rated to operate from -20 C to 85 C. The manufacturer states that the quality exceeds the OEM equipment and that all products shipped are tested.
Key Features
- Brand new aftermarket voltage regulator rectifier
- Direct replacement for your original unit
- Plug-and-play, direct fit, easy installation
- No assembly required
- Higher grade of electric components
- Improved heat sink and charging capabilities
- Quality exceeds the OEM equipment
- All products shipped are tested
Technical Specs
| Specification |
Detail |
| Part number |
RMS020-103973 |
| Width |
60 mm |
| Length |
68 mm |
| Height |
20 mm |
| Number of plugs |
1 |
| Number of pins |
5 |
| Minimum charging voltage |
14.5 V +/- 0.5 V |
| Maximum charging current |
50 A / 500 W |
| Open circuit voltage |
Less than 15 V |
| Operation temperature |
-20 C to 85 C |
Vehicle Fitment Guide
Years shown are the overall coverage span for this part. Please confirm against the OEM part number on your original unit before ordering.
| Make & Model |
Years |
| Aprilia SX 50 |
1993-2020 |
| Derbi 50 |
1993-2020 |
| Gilera RCR 50 |
1993-2020 |
| Malaguti F15 |
1993-2020 |
| Piaggio Zip 50 |
1993-2020 |
| Vespa LX 50 |
1993-2020 |
OEM Part Number Cross Reference
Aftermarket replacement. OEM part numbers are listed for reference only.
| Part Number |
Manufacturer / Brand |
| 641788 |
OEM cross reference |
| AP8224370 |
OEM cross reference |
| 9693825 |
OEM cross reference |
| 02602800 |
OEM cross reference |
| 639751 |
OEM cross reference |
Frequently Asked Questions
Will it fit without modification?
Yes. It is a plug-and-play, direct fit replacement using the same single five-pin plug as the original, so no assembly and no rewiring is needed.
What is included?
One brand new aftermarket voltage regulator rectifier, part number RMS020-103973. No additional hardware is listed for this part.
How do I know the old regulator has failed?
With the engine running the charging system should show at least 14.5 V plus or minus 0.5 V at the battery. A scooter that repeatedly flattens its battery, blows bulbs, or shows a reading above the 15 V open circuit limit is usually telling you the regulator has failed rather than the battery.
Why does the improved heat sink matter on a 50 cc scooter?
A regulator sheds surplus charge as heat, and on a small scooter it usually sits in a tight, poorly ventilated space. The larger heat sink on this unit moves that heat away more effectively, which is what allows the improved charging capability and lengthens the life of the part.
Dispatched from the UK · 12-month warranty · Fitment support from our technical team
