First Ever Failure - Regulator/Rectifier

In my eight years of WR400/450 ownership, I finally experienced a component failure. After blowing three bulbs in a row on my 450 and THEN (:thumbsup:) deciding to investigate/troubleshoot the issue, I narrowed it down to a blown Regulator/Rectifier. The output at the bulbs was between 20-25 VAC depending on rpm, while strangely enough the output across the battery never exceeded ~14 VDC. The battery never discharged and the e-start always worked, so the DC side of the R/R seemed to be working fine. While troubleshooting, I went through the process of disconnecting/connecting/cleaning all connectors with no success, so I finally borrowed a R/R from a friend's 450, and problem solved! The output at the headlight was now 9-12 VAC depending on rpm. A couple of minutes on ebay and $45 later, I'm back in business with a used 2007 WR250F Regulator/Rectifier.

In my eight years of WR400/450 ownership, I finally experienced a component failure. After blowing three bulbs in a row on my 450 and THEN (:thumbsup:) deciding to investigate/troubleshoot the issue, I narrowed it down to a blown Regulator/Rectifier. The output at the bulbs was between 20-25 VAC depending on rpm, while strangely enough the output across the battery never exceeded ~14 VDC. The battery never discharged and the e-start always worked, so the DC side of the R/R seemed to be working fine. While troubleshooting, I went through the process of disconnecting/connecting/cleaning all connectors with no success, so I finally borrowed a R/R from a friend's 450, and problem solved! The output at the headlight was now 9-12 VAC depending on rpm. A couple of minutes on ebay and $45 later, I'm back in business with a used 2007 WR250F Regulator/Rectifier.

Is your stator stock? If so, its a regulator only! :thumbsup:

Is your stator stock? If so, its a regulator only! :thumbsup:

Hmmm.....the stator is stock. If it's a regulator only, what's converting the stator AC output voltage to DC for charging the battery?

Hmmm.....the stator is stock. If it's a regulator only, what's converting the stator AC output voltage to DC for charging the battery?

Oh many I was out in left field when I typed that...totally forgot that :thumbsup:

Hey SXP, I have the same problem with my wr450 2003 model.

The battery is fine starts fine runs fine but i have blown 6 headlight bulbs and 2 tail light bulbs.

I only got about a min of riding the other day before it blew, I just gave it a handfull of throttle and found the light wouldnt work (low beam) after that.

So how do you check the regulator and see if it is giving out too much voltage?

i started the bike and ran the red connector on my multimeter tot he yellow wire on the rectifier/regulator and the black connector to the black wire on the single connector and gave her a rev and it went up to 22 to 24 volts so i would suggest my regulator or rectifier is stuffed????? yes???

can i put a 24v bulb in the headlight so it doesnt keep blowing?

can i put a 24v bulb in the headlight so it doesnt keep blowing?

Put in a 110v AC house bulb. That should cover it.

Or you could solve the problem by putting in a regulator. Trail Tech, Baja Designs, Eline, Electro Sports, ETC all sell regulators. I would think that you would spend more time trying to track down a 24v H4 bulb or doing some type of mode than it would be to actually replace the part that is causing the issue (root cause)

Edited by Chengshin Ripper

None of the aftermarket regulators will work with the stock stator in its stock form.

Hey SXP, I have the same problem with my wr450 2003 model. The battery is fine starts fine runs fine but i have blown 6 headlight bulbs and 2 tail light bulbs. I only got about a min of riding the other day before it blew, I just gave it a handfull of throttle and found the light wouldnt work (low beam) after that. So how do you check the regulator and see if it is giving out too much voltage?

With your multimeter on the VAC setting measure the voltage across the terminals in the headlight socket. With the engine running and while blipping the throttle if you are reading in the 20+volts range then you have a bad regulator. It should read around ~12V.

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