This is a red machined aluminium MOSFET voltage regulator built for enhanced heat dissipation. RMSTATOR states that after 10 minutes of use the billet aluminium heatsink runs 33 percent cooler than a standard cast housing, which is the single biggest factor in regulator life on a hard-worked sportbike. The unit uses MOSFET regulation technology for three-phase permanent magnet charging systems.
Unlike a plug-in replacement that inherits every weakness of the original loom, this regulator bypasses the vehicle wiring harness and connects directly to the battery through ring terminals, removing the connector voltage drop that causes so many repeat charging faults. Overheat protection means the unit shuts down temporarily rather than failing outright. Installation is plug-and-play, direct fit, with no assembly required.
Key Features
- Billet machined aluminium heatsink - runs 33 percent cooler than standard cast after 10 minutes of use
- MOSFET regulation for three-phase permanent magnet charging systems
- Harness bypass - connects straight to the battery on ring terminals
- Overheat protection shuts the unit down temporarily instead of letting it burn out
- Rated to 50 A / 500 W maximum charging current
- Plug-and-play, direct fit, no assembly required
Technical Specs
| Specification |
Detail |
| Width |
95 mm |
| Length |
90 mm |
| Height |
30 mm |
| Wire lengths |
811 mm and 350 mm |
| Fixation holes, centre to centre |
75 mm |
| Number of plugs |
2 |
| Number of pins |
5 |
| Number of wires |
5 |
| Minimum charging voltage |
14.5 V +/- 0.5 V |
| Maximum charging current |
50 A / 500 W |
| Open circuit voltage |
Under 15 V |
| Operating temperature |
-20 C to 85 C |
Vehicle Fitment Guide
Please confirm against the OEM part number on your original unit before ordering.
| Make & Model |
Years |
| Honda CBR 600 F4i |
2001-2004 |
| Honda CBR 900 RE |
2001 |
| Honda CBR 900 RR |
2001-2002 |
| Honda CBR 929 RE |
2001 |
| Honda CBR 929 RR |
2000-2001 |
| Honda VFR 800 Interceptor |
2002-2009 |
OEM Part Number Cross Reference
Aftermarket replacement. OEM part numbers are listed for reference only.
| Part Number |
Manufacturer / Brand |
| 31600-MBW-D21 |
Honda |
| 31600-MBW-A10 |
Honda |
| 31600-MCJ-640 |
Honda |
| 31600-MCJ-641 |
Honda |
| 31600-MCW-D01 |
Honda |
| 31600-MCW-D60 |
Honda |
| 31600-MCW-D61 |
Honda |
Frequently Asked Questions
Will this fit without modifying my bike?
Yes. It is a direct fit, plug-and-play unit with 75 mm centre-to-centre fixation holes and no assembly required. The one difference from a standard swap is the bypass: the two battery leads terminate in ring terminals that go straight onto the battery posts rather than back through the original harness.
What does the harness bypass actually do for me?
It takes the original main harness connector out of the charging circuit. On these models that connector is a common source of voltage drop and repeat charging faults, so routing the output directly to the battery removes the weak link rather than replacing it.
How do I know my old regulator has failed?
Measure the voltage across the battery with the engine running. A healthy system should reach at least 14.5 V +/- 0.5 V. A reading that stays near battery resting voltage points to no charge, and a reading well above 15 V points to an overcharging regulator that will boil the battery. Discoloured or melted connector pins on the old unit are another clear sign.
Why does a machined aluminium body matter?
Regulators fail from heat. RMSTATOR measured the billet aluminium heatsink running 33 percent cooler than a standard cast housing after 10 minutes of use. On top of that, the MOSFET design includes overheat protection, so if the unit does get too hot it shuts down temporarily and recovers instead of burning out permanently.
Dispatched from the UK · 12-month warranty · Fitment support from our technical team
