Part RM30408 is a brand new voltage regulator rectifier supplied as a direct replacement for the original unit fitted to the Honda VT 1100 Shadow from 1987 through to 2007. It is a plug-and-play, direct fit component: the three plugs, seven pins and seven wires match the factory arrangement and the fixation holes are 75 mm centre to centre, so the unit bolts to the original bracket with no assembly and no modification to the wiring loom.
The regulator rectifier sits between the stator and the battery. It rectifies the alternating current produced by the alternator into direct current and then regulates that output so the battery and the rest of the electrical system see a stable voltage. This replacement is built with a higher grade of electric components and an improved heat sink, giving better heat dissipation and improved charging capabilities, and the manufacturer states that the quality exceeds the OEM equipment. Every unit is tested before it leaves the factory.
The kit also includes the opposite connector for the main harness side. Original harness connectors on high-output cruisers are commonly found melted, corroded or otherwise defective, and replacing that connector along with the regulator removes one of the most frequent causes of a charging fault that keeps coming back.
Key Features
- Brand new direct replacement for the original Honda unit
- Plug-and-play, direct fit, easy installation
- No assembly and no loom modification required
- Improved heat sink and improved charging capabilities
- Higher grade of electric components
- Quality exceeds the OEM equipment
- Supplied with an additional main harness side connector
- Three plugs, seven pins, seven wires
- Long 630 mm and 635 mm leads for easy routing
- Tested before shipping
Technical Specs
| Specification |
Detail |
| Part number |
RM30408 |
| Width |
80 mm |
| Length |
103 mm |
| Height |
32 mm |
| Fixation holes centre to centre |
75 mm |
| Wire lengths |
630 mm and 635 mm |
| Number of plugs |
3 |
| Number of pins |
7 |
| Number of wires |
7 |
| 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 C to 85 C |
Vehicle Fitment Guide
| Make & Model |
Years |
| Honda VT 1100 Shadow |
1987 - 2007 |
OEM Part Number Cross Reference
Aftermarket replacement. OEM part numbers are listed for reference only.
| Part Number |
Manufacturer / Brand |
| 31600-MAA-000 |
Honda |
| 31600-MAA-A01 |
Honda |
| 31600-MAA-A10 |
Honda |
| 31600-MAH-008 |
Honda |
| 31600-MCK-A01 |
Honda |
| 31600-MCK-A51 |
Honda |
| 31600-MM8-008 |
Honda |
Frequently Asked Questions
Will this fit my VT 1100 Shadow without modification?
Yes. RM30408 is a direct fit, plug-and-play replacement. It carries the same three plugs, seven pins and seven wires as the original, and the mounting holes are 75 mm centre to centre to suit the factory bracket. No cutting, splicing or assembly is needed.
What is included?
You receive one voltage regulator rectifier complete with its connector assembly, plus an additional connector for the main harness side. That extra connector is supplied because original harness connectors are so often melted or corroded by the time the regulator itself fails.
How do I know my old regulator rectifier has failed?
Measure the voltage at the battery terminals with the engine running. A working charging system should reach at least 14.5 V +/- 0.5 V. A reading that stays at or below resting battery voltage suggests the unit is no longer charging; a reading much above 15 V suggests it has lost regulation and is boiling the battery. Browned or melted connector shells are another clear sign.
Are the leads long enough to reach the original mounting position?
The unit is supplied with 630 mm and 635 mm leads, which are generous for a regulator of this type and allow the connectors to be routed to the factory positions without extending the harness.
Dispatched from the UK · 12-month warranty · Fitment support from our technical team
