This is a brand new aftermarket voltage regulator rectifier built as a direct replacement for the original unit fitted to the Honda CRF 250 R and CRF 450 R competition four-strokes. It is a plug-and-play, direct fit part: the case dimensions, the 65 mm fixation hole spacing and the single four-pin plug all match the factory component, so the unit bolts into the original bracket and connects to the standard harness with no cutting, splicing or adapters. No assembly is required before fitting.
The regulator rectifier is the component that converts the alternating current produced by the stator into direct current, and then holds that output at a level the battery and the lighting circuit can tolerate. On a high-revving motocross engine it works hard and it works hot, which is why it is one of the most common electrical failures on these models. This RMSTATOR replacement is built with a higher grade of electrical components than the original, to a standard the manufacturer states exceeds the OEM equipment, and every unit is tested before it is shipped.
Key Features
- Brand new aftermarket unit, not a repaired or rebuilt core
- Direct replacement for Honda OEM part 31600-MEN-A31
- Plug-and-play fitment - single plug, four pins, no wiring modification
- Higher grade electrical components than the original equipment
- Regulated output of 14.5 V +/- 0.5 V to protect the battery
- Rated to a maximum charging current of 50 A / 500 W
- Every unit individually tested before dispatch
Technical Specs
| Specification |
Detail |
| Part number |
RMS020-107247 |
| Width |
64 mm |
| Length |
86 mm |
| Height |
20 mm |
| Fixation hole spacing (centre to centre) |
65 mm |
| Number of plugs |
1 |
| Number of pins |
4 |
| 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 CRF 250 R |
2010-2012 |
| Honda CRF 450 R |
2009-2012 |
OEM Part Number Cross Reference
Aftermarket replacement. OEM part numbers are listed for reference only.
| Part Number |
Manufacturer / Brand |
| 31600-MEN-A31 |
Honda |
| RMS020-107247 |
RMSTATOR |
Frequently Asked Questions
Do I need to modify anything to fit this regulator?
No. This is a direct fit, plug-and-play replacement. It uses the same single four-pin plug as the original and the two mounting holes are spaced 65 mm apart, centre to centre, exactly as on the factory unit. No cutting, no splicing and no assembly are required.
What do I receive?
You receive one brand new aftermarket voltage regulator rectifier, part number RMS020-107247, tested and ready to fit. No mounting hardware or wiring loom is listed as being supplied with this part, so retain your original bolts.
How can I tell that my old regulator has failed?
The usual signs are a battery that will not hold charge, a charging voltage that stays at or below battery voltage with the engine running, or a charging voltage that climbs well above the regulated 14.5 V and boils the battery. Blown bulbs, a swollen battery case and a regulator body that is too hot to touch shortly after starting all point the same way. Measure the voltage across the battery terminals with the engine running and compare it against the 14.5 V +/- 0.5 V figure in the table above.
Will it cope with the CRF 450 R as well as the 250?
Yes. The same unit is specified for the CRF 250 R from 2010 to 2012 and the CRF 450 R from 2009 to 2012, and it is rated to a maximum charging current of 50 A / 500 W with an operating range of -20°C to 85°C, which covers both applications.
Dispatched from the UK · 12-month warranty · Fitment support from our technical team
