This is a brand new aftermarket voltage regulator rectifier for the Honda CR125R of 2004 and the Honda CR250R built between 2002 and 2007. It is supplied as a direct replacement for your original unit, so it is a plug-and-play, direct fit part that needs no assembly and no modification to the machine or its wiring loom.
The unit measures 62 mm long by 32 mm wide and 17.5 mm high, with a single plug carrying four pins and four wires. Two wire lengths are supplied on the unit, 60 mm and 390 mm, matching the original harness routing on these two-stroke motocross bikes. It is built from a higher grade of electric components than the original part, and the manufacturer states that the quality exceeds the OEM equipment. Charging voltage is held at a minimum of 14.5 V plus or minus 0.5 V, maximum charging current is rated at 50 A or 500 W, open circuit voltage stays below 15 V, and the unit is rated to work from -20 C through to 85 C. Every unit is tested before it is shipped.
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
- Quality exceeds the OEM equipment
- All products shipped are tested
- Replaces Honda part number 31600-KZ3-J41
Technical Specs
| Specification |
Detail |
| Part number |
RMS020-103806 |
| Width |
32 mm |
| Length |
62 mm |
| Height |
17.5 mm |
| Wire lengths |
60 mm and 390 mm |
| Number of plugs |
1 |
| Number of pins |
4 |
| Number of wires |
4 |
| 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
| Make & Model |
Years |
| Honda CR125R |
2004 |
| Honda CR250R |
2002-2007 |
OEM Part Number Cross Reference
Aftermarket replacement. OEM part numbers are listed for reference only.
| Part Number |
Manufacturer / Brand |
| 31600-KZ3-J41 |
Honda |
Frequently Asked Questions
Does anything need modifying to fit it?
No. This is a plug-and-play, direct fit replacement that uses the original four-pin plug and the original mounting point. No assembly is required and nothing on the bike needs cutting, drilling or rewiring.
What is included?
One brand new aftermarket voltage regulator rectifier, part number RMS020-103806, with the 60 mm and 390 mm wire tails already fitted. No additional hardware is listed for this part.
How do I know the old regulator has failed?
Measure the voltage at the battery with the engine running. The charging system should hold at least 14.5 V plus or minus 0.5 V. A reading that stays low, or one that climbs past the 15 V open circuit limit and cooks the battery, points at the regulator rather than the battery or the stator.
My CR250R is a 2005. Is this the right part?
Yes. The CR250R is covered for the whole 2002 to 2007 run, and the CR125R for 2004. If you want to be certain before ordering, check that the number on your original unit reads 31600-KZ3-J41.
Dispatched from the UK · 12-month warranty · Fitment support from our technical team
