2005 WR450f headlight doesn't work

I recently picked up this bike and it starts and runs great, i have started it at least 15 or 20 times with the E start and it fires right up, which tells me the stator is good…right?        i started tracing the wires in the harness for the headlight and there doesn't seem to be any bad connections and i pulled apart all the plugs to make sure they were making contact.     looks like the yellow headlight wire runs to the alternator and the black ground runs to battery ground and the blue and another black run the the tail light, is that right?    I'm not electrician so I'm not too sure how any of this crap works…..


when i bought it, both the head and tail light were unplugged. so i plugged them both in and nothing… I'm not too concerned with the tail light, but i really want the headlight to work.    I've seen people with issues of dim headlights, but i have not seen issues with not power at all..  oh and yeah i checked the bulbs, i hooked the headlight straight to the battery and it lit up… and yes i know that it runs on AC, i just wanted to test it. 

anything? charging system? need a new wiring harness?

I have the baja designs kit on mine so I don't know what it's supposed to be like in stock format. Is it possible you could just run a hot wire from the battery to it and put an on/off switch on it?

If the previous owner "floated the ground" on the stator, then you would have to run a wire from the battery up to the headlight to power it. Perhaps this is the case?

It is an extrememey simple circuit because the headlight is supposed to be on all the time 

Im not sure if it even has a hi/lo switch (I now have a Baja Kit on mine so I dont remember)

A yellow wire comes off of the stator and feeds the headlight

The other wire off of the bulb is a Black that goes to ground

If you give me an email address ic can scan the schematic from fact manual and send to you


WARNING: If prev owner floated ground, as maniac998 notes above, all bets are off

Below is the explanation/warning that came with my Baja kit:

’03 and newer WR stators are wound with two separate coil outputs from the factory. One output charges the battery for the electric-start and the other output powers the stock lighting via its own AC circuit (no battery backup.) In stock form the battery cannot be used to power any lighting without becoming discharged. The new system produces 100 Watts, so a headlight bulb not exceeding 55 Lo / 60 Hi Watts is req so as to not create a state of discharge. This modification joins the two existing stator outputs together into one and is necessary anytime the stock battery will be used to power a lighting system (such as a dual sport or HID system.)

Once the stator has been modified, the stock rectifier/regulator must be replaced with a Baja Designs unit and the lighting system must be powered via DC from the battery. The stock headlight connector can no longer be used as a lighting power source. Failure to replace the rectifier/regulator or using the stock headlight connector will result in the battery discharging.

Check stator wires I found one of my wires was cut by I think fly weel on my wr09 450.

I'm trying to think of the simplest test to determine if Ground was floated

I think he has to know if he is looking at a stock setup vs something modified.


And above all that check the obvious as Paco says and look for a cut wire


Follow that yellow wire back and see if it gives off 12V when bike running (ther wire to frame or gnd)

not sure if the previous owner did anything with floating the ground or not.       i ended up getting the trail tech 100w dc conversion stator and regulator kit…… i did this after i noticed the battery was not charging…. and when the battery is low, it did not run worth a shit and would barley idle….i charged it back up and it ran great… is this normal?        whats the point of the kick starter if the battery has to be good for it to run?    it ran great when i bought it, but the battery was brand new.        when i took it apart to put the trail tech kit in it there was chunks of metal in between the stator and flywheel from i don't know where and the stator was all bashed up from it…. they looked like little balancing weights or something but upon inspection i don't know where they came from. so i figure i found my problem.  i put in the TT conversion exactly how the directions showed, it was very simple plug and play. i got it all put back together and went to start it and it turns over and over and over and over and over and over with the E start and occasionally the exhaust pops and when the compression builds up it kicks back a little bit. the damn thing won't start up now. i called trail tech and they said its probably because the CDI isn't getting 12 volts.. if it doesn't then what???  i don't have a tester, ill need to borrow one so i started screwing with wires and its too confusing for me. i read online that the white wire to the CDI can be ran directly to the battery through a switch …….so i try that……. and up goes a cloud of white smoke….SHIT! that wire fried and when i looked at the rest of the wires on that unit there is more that are a little chewed up anyways.    so now i ordered a dyna tech or whatever CDI, i hope to god it comes with a factory program so i don't have to &%$#@! with it too. after i put that in then the only thing else it could be is the stupid ass wiring harness right?  this bike has been a pain in my ass and i haven't even taken it out yet.   i have never been good with wiring so i am searching for info online and i am getting a lot of different answers. i wish i could just have someone with some knowledge and the right testing equipment look at it. i am pretty bummed out on my "new" bike.

Damn sorry about all the troubles. Mine is an 05 and when I bought it the battery was dead but it ran fine once started. It was hard to start though. Where is California are you maybe there is a member close that could help you?

Damn sorry about all the troubles. Mine is an 05 and when I bought it the battery was dead but it ran fine once started. It was hard to start though. Where is California are you maybe there is a member close that could help you?

Thanks for the reply. Trail tech had a damn wire crossed in their wiring harness. Thankfully I figured it out. Works great now. The new dynatek ignition is pretty slick


Edited by DonnieD

Have you investigated the metal pieces?  A while back I found fine metal in my oil filter.  As I torn down the engine I found metal pieces stuck to the magnet in the stator pickup.  Turned out to be the forth pinion gear shedding it's teeth.  If I was you I'd investigate further before hitting the trails!

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