Part RM30905 is a brand new improved AC voltage regulator rectifier supplied as a direct replacement for the original unit fitted to the Kawasaki 650 SC, 650 X2 and TS Tandem Sport between 1989 and 1996. It is a plug-and-play, direct fit component: no assembly is required and the compact 46 x 55 x 21 mm body mounts on fixation holes 35 mm centre to centre, matching the original location.
On these machines the regulator rectifier takes the alternating current produced by the ignition and lighting coils and converts it to a regulated direct current output, so the battery is charged at a controlled voltage rather than whatever the engine speed happens to produce. It is a component that lives a hard life in a marine environment, where salt, damp and vibration all shorten its service life, and a failed unit will either flatten the battery over a few outings or overcharge it until the electrolyte boils away.
RMSTATOR build this replacement with a higher grade of electric components, and state that the quality exceeds the OEM equipment. All products shipped are tested. The unit cross references to Kawasaki part number 21066-3708, so if you still have the original to hand you can confirm the application directly from the number moulded or printed on it before ordering.
Key Features
- Brand new improved AC voltage regulator rectifier
- Direct replacement for the original Kawasaki unit
- Plug-and-play, direct fit, easy installation
- No assembly required
- Quality exceeds the OEM equipment
- Higher grade of electric components
- Compact 46 x 55 x 21 mm body
- Five pins and six wires
- Fixation holes 35 mm centre to centre
- All products shipped are tested
Technical Specs
| Specification |
Detail |
| Part number |
RM30905 |
| Type |
AC regulator rectifier |
| Width |
46 mm |
| Length |
55 mm |
| Height |
21 mm |
| Fixation holes centre to centre |
35 mm |
| Number of pins |
5 |
| Number of wires |
6 |
| Minimum charging voltage |
14.5 V +/- 0.5 V |
| Maximum charging current |
25 A / 300 W |
| Open circuit voltage |
Less than 15 V |
| Operating temperature |
-20 C to 85 C |
Vehicle Fitment Guide
| Make & Model |
Years |
| Kawasaki 650 SC |
1989 - 1996 |
| Kawasaki 650 X2 |
1989 - 1996 |
| Kawasaki TS Tandem Sport |
1989 - 1996 |
OEM Part Number Cross Reference
Aftermarket replacement. OEM part numbers are listed for reference only.
| Part Number |
Manufacturer / Brand |
| 21066-3708 |
Kawasaki |
Frequently Asked Questions
Does this need any modification to fit?
No. RM30905 is a direct replacement for the original unit, described as plug-and-play and direct fit with no assembly required. The fixation holes are 35 mm centre to centre and the unit carries five pins and six wires, matching the original arrangement.
How can I confirm this is the right part for my machine?
RM30905 cross references to Kawasaki 21066-3708 and is listed for the 650 SC, 650 X2 and TS Tandem Sport from 1989 to 1996. Compare the number on your existing regulator and the 46 x 55 x 21 mm dimensions with the specification above before ordering.
How do I tell whether the old regulator rectifier has failed?
With the engine running, the battery should see at least 14.5 V +/- 0.5 V. A battery that goes flat over a couple of outings despite being sound points to a unit that has stopped charging, while a reading much above 15 V points to a unit that has lost regulation and is overcharging - often noticed as a battery that boils dry or a strong acid smell in the engine bay.
What output is this rated for?
Maximum charging current is 25 A, equivalent to 300 W, with open circuit voltage held below 15 V. The operating temperature range is -20 C to 85 C.
Dispatched from the UK · 12-month warranty · Fitment support from our technical team
