I have an 04 WR450...it came (used) with an Acerbis Dual beam front light package. Two 35 watt/12 volt halogen bulbs..the type found at any Home Depot.

Last year early in the season the headlights and tail light all blew at the same time while riding. The bike continued to operate just fine. I replaced the lights and rode about 20 times..no problem. At the very end of the season they blew again..I replaced them.


This year I did one ride 4 hours...no problem. The next ride about two minutes in, headlights and tail light all blow again. Whenever this happens the bike continues to run and start no problem. In fact I never notice the problem until after we stop or the ride is over.

When the lights are working they are dim at idle and then brighten up as the RPMs increase and then hold at max brightness...I believe this is normal based on the way the stock electrics work on this bike.

I have put a meter across the red and black cables to the battery and while running at normal (not idle) rpms I get 14.2...14.4 volts. I believe this is normal as well.

Is it an intermitant fault in my regulator/rectifier??
Is it a stator issue??
Am I cursed by the electron gods??

Any insight as to what might be causing this would be greatly appreciated.


Thanks

travertt said:

It shouldn't be too much different idle vs. runnning as the bike has a battery, if the battery is good. Slightly dimmer, but not too much.

May be an intermittant issue, especially with the reg/rect, but what is the voltage above idle like 1/2 throttle, say 3-4,000 rpm? That will tell you much more than idle voltage what is and isn't working.

Doubting stator, but test it to be sure.

Was anything else changed or installed or just the headlight? There is some overhead in the charging system but not a ton so that may be an issue if other electrical things are running.

Also, dirt bikes are much harder on bulbs than cars so if you are using regular car light bulbs you may be beating them to death if everything else tests out. Had an issue on my VFR 750 years ago with high wattage bulbs because of this and it was a street bike. Cycles usually use heavy duty bulbs to combat this.

Hope this helps,

Mike

I would pull some plastics and the tank, trace your whole wiring harness for sections with damaged insulation from abraision. You could have a short to ground that only occurs at a certain loading condition (landing ajump, gust of wind, leg against a panel, etc). I would pay extra attention to the area where you reg/rec is. also look for paint rubbed off of the frame or bare metal where the wirign harness is. Unpainted steel and bare aluminum conduct VERY well. Painted steel not so much...

If you're popping the filament in the bulbs without a significant impact then you have a voltage spike going on. Check the grounds especially for the regulator. Without a good ground reference then regulator can loose control and let the voltage go out of control.

Thanks all.

I will do some "sleuthing" of the wireing with particular care around the regulator/rectifier area...however I'm not very knowledgable when it comes to electrics except for the obvious things like loose connections and physical abrasions.

Is it possible that the actual regulator/rectifier has an intermittant problem ..or is it the kind of component that is either working great or not working at all?

Is there a way to test the regulator/rectifier for inconsistancy or weakness??

Thanks again.

Did you figure your problem out? Jlow

travertt said:

Typically a solid state devise either works or it doesn't. They can have problems and go out of range but usually they are consistent.

However if there's a connection problem inside it can do the same as a ground issue. Unfortunately you'll probably have to confirm the outside circuitry and then just replace the regulator since an intermittent issue usually won't show up on the bench.

Well I replaced all the bulbs and it started right away. After a brief warm up I revved it up to about 3500RPM (Guessing here) and one by one all the bulbs blew in about 10 seconds. The bike was on the stand, not being ridden so there was no violent movement or water issues...just once I started to run at higher RPMS the bulbs got brighter and brighter and then blew.

I went riding anyway and the bike behaved perfectly. So I'm guessing its the rectifier/regulator. It seems to me that if it was a short in the wiring that the bulbs would blow even when the bike was idling...am I wrong in this logic??

Apparantly the bike has a "split system" that converts the stator output to both AC for the lights (the area where I have my problem) and DC for the battery/ignition...this means apparantly that I am stuck with using the OEM regulator as the trail tech etc reg/rect cannot handle this split usage without extensive mods.

Am I correct in assuming that am OEM regulator/rectifier would just "plug in" to the wiring harness somewhere along the upper frame with a multipin connector??

Any feedback or musings on this would be appreciated as I would hate to spend what will no doubt amount to a couple of hundred dollars to get OEM part and dealer service.

Many thanks

The bulbs probably wouldn't blow idling even without a regulator, mine brighten but only to a point. But sitting still I'd have to say the regulator is done.

My understanding of it (While very familiar with electrical I'm not up to speed yet on the WR systems.) is that the lights and other running electrics such as the CDI and coil run off the same side of the stator while the other side of the stator charges the battery, which is why the YZ has a different charging system despite having the same basic ignition system.

Yes, an OE regulator should just plug right in.

Have my stock one off an 08 if it will work. Yours if you need it. Also check with Baja Designs. Bought mine from them when I plated mine. Jlow

Hello everyone who responded to this question some months ago. My life had been somewhat bizarre of late and I failed to respond to all those who took the time to help out.

SO...let me do now...thanks everyone for your help!! especially jlow for the generous offer of his extra regulator/rectifier..much appreciated.

To update (I had re-posted the problem having forgotten about this, my orginal post)...I have solved the issue it seems. I purchased a new reg/rect and installed it yesterday along with new lights everywhere. Things seem to be perfect. The light brighten as I rev the engine (like they always did) and then stabilize at a certain point and further revving does not blow them. I have only been able to test in garage conditions as its mid winter here but it looks good.

Thanks again to all...this is a great forum...made so by the people who take the time to offer help.