08 wr450f electrical problems

6 replies to this topic
  • ak567

Posted September 04, 2008 - 05:31 PM


I have a 08 wr450f fully supermoto converted. only added electrical add ons it has is a break light a rear led turn signals. My problem is my battery wont stay charged. I'll chargemit with a charger and after a days riding it will be nearly dead. Do i now need a bigger stator. only mods it has it the moto converson, asi removed and jetted for the wheels and asi. I will post pics tomorrow and any info would help. also battery is brand new.

  • Thumper_Bloke

Posted September 04, 2008 - 06:50 PM


You need to check the Voltage of the battery at idle and mid-range.

Tell us what the voltage at the battery is:
1) With the bike off
2) With the bike idling
3) With the bike revving in mid range

  • face_plant

Posted September 05, 2008 - 06:21 AM


there has to be a bad ground or direct short, make sure the switch is off when its turned off

i can power 4 led t/s 1 ic horn and a led tail light and still put out 13.2
and the headlight is on a separate leg of the stator

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  • ak567

Posted September 05, 2008 - 01:19 PM


Ihave tried to batteries. the stock yusa and the yusa which is designed specifically for the wr450f. I have a horn and headlight as well (the whole street legal kit. A mechanic at yamaha told me i needed a bigger stator. I was also talking to a guy 2day with a 02 crf450 and he said with his kit there was a bigger stator included.

  • Thumper_Bloke

Posted September 05, 2008 - 02:24 PM


Oh, i had no idea that your kit modified the wiring to the headlight. The stock WR wiring to the headlight should be left alone, since it runs off of AC and not the battery.

  • William1

Posted September 05, 2008 - 04:08 PM


Did you leave the stator unmodified as well as the regulator? If so, the stock setup does not output enough power to keep the battery charged and run everything.
The stock stator has two circuits. One that charges the battery the other, runs the headlight. You modify the stator to combine the two circuits, use a larger regulator/rectifire to handle the increased output. This setup requires the headlight to be run off of the battery as there is no longer a lighting output from the stator.

LOL, this all assumes you do not have a contant drain of some sort. You can easily check for this by putting a small light between the battery cables (disconnect the negative wire at the battery, put like an 1156 (turn signal incandesant bulb) to the wire and battery and see if it lights, with the bike switch off. If it does you have a circuit constantly draining. After the light buld test, put a small amp meter there and see the draw (switch off or you may cook your meter). A tiny draw (a few milliamps) is to be expected as some power flows to keep the clock working.

  • roushxteam199

Posted September 05, 2008 - 04:18 PM


i had to do the stator mod to my 03. i have no problem running my led tail light with led turn signals. i also run an electric fan and my vapor


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