Need Help WR400 Electrical Question

5 replies to this topic
  • caracas400

Posted April 09, 2014 - 07:22 PM


I just purchased a 1999 WR400, long story short I changed the entire engine! When putting everything back together I have misplaced the regulator.

My question is can i start the bike with out the regulator?
Does the CDI work off the regulator?
Can I put a universal regulator?

Thank you for your responses.
I live in south america and spare parts for this model bike are very hard to find and expensive.

  • flyandride

Posted April 09, 2014 - 09:30 PM


Here's the wiring diagram for your bike.  The regulator controls the voltage coming off the lighting coil.  I see a lead going from the lighting coil to the CDI.  If the regulator was missing, the voltage to the lights, and CDI would go high enough to burn out the bulbs.   I don't know what it would do to the CDI but I wouldn't risk it.  


You might be able to use an AC regulator from another bike.  Trail Tech makes an AC regulator that would work.  Most of the universal regulators I see are for bikes with a DC system, you would have to reconfigure the whole system and may need a battery for them to work.  


Do you have ebay where you live?  I see lots of used voltage regulators that would work on your bike.  

Attached Thumbnails

  • 98WR400F wiring.jpg

Edited by flyandride, April 09, 2014 - 09:31 PM.

  • caracas400

Posted April 10, 2014 - 06:05 AM


Hi thanks for the reply. I can order from ebay and it gets shipped to Miami and then I have to shipp it over. The process takes about a month. There is an ebay look a like here and I found 3 regulators for a Skygo 250 its like a knock off supermoto chinesse made. I will post the fotos.

How do I know if a bike is AC?

ImageUploadedByThumper Talk1397138608.460431.jpg
ImageUploadedByThumper Talk1397138707.727320.jpg

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  • GuyGraham

Posted April 10, 2014 - 10:12 AM


coz all bikes are AC

the reg/rec converts the AC current from the stator to DC for charging the battery etc

  • flyandride

Posted April 10, 2014 - 05:28 PM


Those regulators in the pictures have 4 wires, they are for a DC system with a battery and won't work.  Your bike is AC with no battery.  

This one would work if you can get in where you live.

  • caracas400

Posted April 11, 2014 - 03:27 PM


Hi just started the bike today with out the regulator, when around the block until I notice the valve cover half moons were not seated correctly and oil was dripping out rapidly. Will have to work on that. Thanks for the sugestions!


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