03 wr450 Charging problem

I have an 03 wr450 that I have recently installed the baja designs dual sport kit.The charging system isnt working.When I rev the engine the lights get dimmer.The voltage at the battery drops, when tested with a volt meter, as rpms rise.I sent an e-mail to baja designs, explaining the situation.I recieved an e-mail back a couple days later stating the likely cause is a bad regulator/rectifier.The guy told me he has seen a lot of rectifiers going bad on these bikes, both with and without the dual sport kit.I sent him another e-mail, stating my concerns about frying another regulator, and that it seemed unlikely to me that it would just happen to go bad at the exact same time as I installed the kit.Its been a couple weeks now and I havent heard anything back.I did buy another regulator and that didnt fix the problem.The only other thing I can think of trying is the charge coil.If anybody has had a similar problem, or has suggestions on what I might try next, I would appreciate the feedback. Thanks.

You should be able to check the coil output with a multitester set on the AC setting. The tester wires go to both coil wires from the coil. The AC gets changed to DC by the rectifier so change the meter to the DC setting to test. Can you unhook the Baja wiring and go back to the stock setup to test? Check all wires and connections, you may just have a bad ground. The bikes service manual has a good section on how to test for problems. If stumped offer an electrician a six pack to help. Good Luck!

I suspect Baja Designs of BS....it sounds more like their product is at fault....the only late-model WRs I've heard of having this problem have Baja Designs kits on them!

Yes, I agree with Rich Baker.

I also suspect the Baja Designs kit. :D

I am not an electrical expert by any means but....

I also purchased the kit for my wr450 and RETURNED IT.

The reason that you are having charging problems is due to the way the kit is designed!

Baja's Designs offers the kit with their standard handlebar turn signal switch. This standard switch is designed for DC current only (like the old XR's etc.)

However.... our WR's are both AC and DC like you said (as are the new KTM enduros I beleive.

For whatever reason Baja Designs has not yet re-thought this design.

I spoke with the guys at Baja a few times and was told that the WR's have a screwy wiring design and it causes regulator problems but it is only the bikes with the Baja kits that have this problem.


By running your headlight and tail/brakelight on DC you are putting a huge load on that little battery and that poor regulator. It's a great little battery but not a car battery.

You are going through the same thing that I did 2-3 months ago.

DO A FEW SEARCHES (Baja, Dual sport, regulator, etc.)

You will find our discussions regarding this EXACT topic.

5spoke, NL7SC and the boys will back me up on this one.....

Send the kit back for a full refund like I did and tell them to let you know when they have designed one that works properly.

THEN, make a kit on your own. Yes, I am serious.

We'll help you. I was skeptical of doing it myself but it really isn't that hard and WAYYYY cheaper.

For the love of God leave your headlight on AC and use your stock bulb 55/60 (not a 35w !!! come on Baja!! not acceptable)

Replace the regulator/rectifier that the kit damaged, remove the Baja Designs kit and send it back to them for a refund. Tell them to talk to us on this site if they like. (they know what "Thumper Talk" is)

I/We will help you wire your own kit. I have all part numbers required and am glad to give you all the info that i have. K&S Brand parts are exactly what we need to wire our bikes the way they should be. The circuits on the handle bar switch are all separate and allow you to run the headlight (Hi/Low beam), tail/brakelight on AC and the horn and signals on DC.

Do search on our previous discussions you'll see.

I made a post asking everyone if they have blown regulators on stock bikes (with no Baja Kit) and there were NONE.

THE PROBLEM IS THE BAJA KIT. (Sorry to anyone that has one!)

It seems that the Baja Designs guys are telling you the same thing they told me.... LIES!

Do your bike right... Do it yourself.

How can we help dude?????????????????????

Just ask. :)

I hope this made sense..... Damn I'm still pissed at those guys. :D

I am really happy with my Trick Dual Sport kit from Angel Scientific. Check them out if you are in the market for a unit that works very well and Dale stands by his product! Link:


You guys were right. I removed the Baja kit, except for the lic. plate brkt. and brake switch, and what do you know , it charges again. So I guess I spent 350 bux on those 2 items.I really did take it up the a** on this one. When you figure the 350 kit price plus the regulator $70.00 ( that cannot be returned) , and the week or so of screwing around trying to figure it out.Well hopfully, my lesson will help others from making this mistake.Thanks for the help. This forum has been very useful in making my wr into a pretty decent bike.

I agree. I do not deal with Baha Designs any more. I have dealt with them in the past and was also very disappointed. They wont get a penny from me. They have bad service and some bad kit designs. :)

Have you fixed the problem? Mine does the same. I bought a Blitz (acerbis)headlight because it looked cool. I got the bike used from a dealer with a street kit on it. I assumed I had a dead bat and took it out

With the light on the rev limiter kicks in, with the light off the thing runs great

i have the same problem. the answer is to wire the headlight directly AC and leave the rest DC. i will have to find the post for this.

I have not yet done this because i ride 95% of the time during the day and i just leave the headlight off.

I will look for it and post the directions.

I have been running the B.D. kit on my 03 WR450 for about a year now and have had no problems at all. It seems that they have put out a couple of differant variations of their kit. The kit I have only runs the brake/taillight and horn off of DC. everything else uses AC as before. I don't know why they would have more than one variation but it seems they do. I have also heard that other kits have come with a 35/35w bulb because they are running off the battery. Mine came with a higher 75/70w xenon bulb. (stock is 60/55w)

I was very impressed with the ease of installation and instructions. It is a clean tight install.


Something to consider.

they must have different kits out there, mine came with a 35/35 watt headlight bulb. if i turn my headlight on, mu blinkers will not work and my battery is drained. after about an hour of riding with the headlight on the electric start will not work.

i have simply not used the headlight unless i have to. i have gotten instructions on this site about wiring the headlight to run directly off the AC side but have not tried it yet.

I just spoke to Dan at Baja Designs and he told me that the original design was confiqured for the headlight to run off just Ac but several voltage regulators went bad causing the headlight bulb to blow so they changed up the design and went with a 35/35 watt bulb but they are aware of the charging problems.

anyway, they have come up with a fix for this and it should be ready in a few weeks, they will be routing all power to a newly designed regulator that they claim will solve this problem.

they are suppossed to contact me when its ready and i will post it here! :thumbsup:

Does this effect EXCs or just WRs ?

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