KDXRIDER.NET

first off, the wiring on my KDX is a mess and should really be replaced

I am running a LED tail/brake light and that works
I am TRYING to run a headlight and it keeps blowing up

I hooked up a multimeter and with that set at 200 VAC it reads 8-9 volt at idle and as much as 28 when revving (the stator has been rewound)
I tried swapping out voltage regulators but the read out was the same


I know I SHOULD replace the wiring and go from there but in the mean time this is my daily driver and I would like to get some type of light going

any ideas ?

Find a better mechanic.

rbates9 wrote:Find a better mechanic.

if I could find one that was affordable I would

Have you looked thru the wiring and made sure that everything is wired in the correct way and you don't have any broken wires?

yes I did, best I can tell its all good

I even tore the tape off the main loom because I couldn't see where the brown one coming from the regulator went
(turned out it joins the red wire heading to the headlight switch)

now, I can get the headlight going, I just cant keep it going
as soon as I rev the bike the bulb will pop

Not sure of what year you have, but my '89 didn't have a voltage regulator. Great design by Kawasaki, one light blows, the other one goes because of the voltage spike it gets. I think Kawasaki started putting them on the '90.

Oops, sorry, didn't see it mentioned in the previous post.

for what its worth it is 96
I tried 2 different voltage regulators both with the same read-out

stock headlight?

no, this bike has seen an array of different lightning set-ups
right now the head light is a KLX knockoff converted to H7

Get a better voltage regulator, the ones that came on them weren't designed for that. On my atk I'm going to try a reg/ rec from a kawi 650 jet ski I have laying around, it should be good enough because the have multi pole stators.

Just a thought, due to you running a LED tail light, is it not drawing as much voltage as a normal bulb and the therefore the headlight getting to much.

The quick answer is a more robust VR, but not really the correct answer. The KDX system is extremely simple, and is the reason that you see the lights pulse with the RPMs. Make sure all your grounds are really good and clean and then coat them with dielectric grease, goes for all the connections really. The correct fix is a small battery and a regulator/rectifier as RoadHazard suggests (ala Baja Designs). It is the only way you'll get clean, regulated 12 v out of our bikes.

rbates9 wrote:Have you looked thru the wiring and made sure that everything is wired in the correct way and you don't have any broken wires?

just had an epiphany, I have a second KDX sitting just a few feet from this one that does NOT have the same problem
so I went ahead and tore into that one and started comparing, this is what I found

wiring near the headlight on the bike without the problem



wiring near the headlight on the bike that keeps blowing bulbs



seems like the headlight isn't grounded out properly
I addressed the problem and restored the wiring to its original set-up and tried it out for a little while with a test bulb, so far, all is well

no time to play with it tonight since the wifey is graduating so ill have to go there, hopefully ill have an update tomorrow

You're diagram is missing the VR which should have a black/yellow wire to ground and a brown (if I remember correctly) to the red. The way you had it wired up is not a surprise you blew a few bulbs, wouldn't be surprised if it killed the VR as well.

the voltage regulator was wired in (like it shows in both drawings) but I didn't bother to color in those lines
if you think it fried it though (I don't know jack about electrical...I only know how to diagnose it : if you cant fix it with a hammer its an electrical problem) I could swap it out no problem with the one from the project bike

I'm not really an electricity expert so someone correct me if I'm wrong.

According to your drawings the problem bike had the headlight and taillight wired in series when they should be in parallel (like the working bike).
In series your lights are splitting the voltage (ie one gets 8 and the other 4 or something) but not the current. So your headlight was having too much current pass through it and blowing a bulb.
If it was hooked up this way (and you aren't mistaken with your drawing) when the headlight blows the taillight will shut off.
Hook it up in parallel and you should be good assuming the regulator didn't fry.

That is the '89 schematic which doesn't show a VR as Kawasaki didn't install them until '90 and didn't update the manual. So, you say the VR is wired in like in the schematic but there isn't one in the schematic. I'm confused!

I guess I didn't catch that
I presumed it was part of the wiring I didn't bother color coding

so to rephrase that, the voltage regulator IS there and unmolested


Thral, I don't know what is going on, but when the front blows the tail stays on and the brake light stays operational

For future use and helpfulness...this problem is resolved?

The questions were correctly answered and would have taken care of the problem if followed, but the last input is, '...I don't know what is going on...'

What IS going on?

what ever the black ground wire was was not essential as a grounb BUT it was essential in the voltage regulators workings

once I rewired it as shown in the first drawing (ground to the black which happens to be where the voltage regulator wires into) everything works as it should


to my previous "I don't know whats going on" statement, the blowing out of the headlight did NOT affect the tail or brake light, both of those have worked flawlessly