Zapped Myself... I thought the KDX was weak?

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seniorsehas
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Zapped Myself... I thought the KDX was weak?

Post by seniorsehas »

My 1995 KDX200 did not come with a headlight. Previous owner took it off and now I'm left guessing at the wiring. My assumption is that I need to hook my new light up to the Yellow and Orange wires near the coil. I did this while the engine was running. I was holding frayed wires from the bike to the light and it lit up dimly. Then I touched my forehead against the handlebar and got a very surprising shock from my forehead to my hands. I'm used to 12volt car systems. Not sure what's coming out of this thing but enough to hurt.

Looking at diagrams now I'm seeing there is a headlight switch installed stock. Is this right?

Is the bike fame "grounded" like a car? Should I only need one wire to my light and ground the negative from the light to the body?

I've read a lot on how the KDX stator isn't that powerful but this think zapped the hell out of me. Is this an indication that someone suped it up? There's no way this was only 12volts.

I feel like a puss here getting shocked by something that isn't powerful enough to run a street legal kit so I'm guessing I'm screwing something up. Any help is hugely appreciated!
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Zapped Myself... I thought the KDX was weak?

Post by pumpguy »

I just finished wiring up mine for lights and horn. Turn signals are not required in Illinois.

Coming out out of the magneto is a yellow wire. That's the power lead from the lighting coil. All your lighting is powered off that, and it is also wired to the regulator which as I understand it, is there to absorb extra load so you don't burn out bulbs or fry wires.

To check the circuit for continuity and function, I found a 12 VAC 18W power source for an electronic appliance. I cut off the output plug and attached alligator clips to each lead. Attach one lead to the downstream yellow lead (male plug side) of your lighting circuit where it attaches to the yellow lead (female socket side). Attach the other alligator clip to ground. Ideal location is the bolt that holds the ignition coil to the frame.

The stock lighting system is AC, so it doesn't matter which alligator clip is attached to circuit's power lead or frame ground. It's stock output is around 40 watts, which is barely adequate. I upgraded to an 85 watt coil to power a stop light and dual filament head light bulb.

The horn I am using is DC only, so I set that up on a separate circuit, powered by a rechargeable 9 volt RC car battery wired to a horn button. For this, I ran the insulated black (-) wire back to the battery, keeping the 2 circuits separate. It beeps just fine, but I have to remember to recharge the battery once in a while.

This test set up has enough current to power your system without having to start the engine. You can also use a continuity tester to sort out the circuity, but that won't provide enough current to actually power up the lights.

You are correct, stock, there was a light switch. Input wire from lighting coil is yellow, output to lights is red.

You should be able to find here or online elsewhere a copy of the stock lighting circuit. These are published in both the owners manual and the service manual.

Sorry, I'm not savvy enough to post it here for you, but if you send me or post your email, I can send it to you that way.

Good luck.
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Re: Zapped Myself... I thought the KDX was weak?

Post by Tyl3r »

Is the voltage regulator connected/functioning properly? I believe you could test the voltage across those two wires with the regulator connected/disconnected to see if there is a difference. That may be the source of the higher than normal voltage. I believe the regulator shouldn't allow the voltage to go above 15V if it is connected and good. I'm kind of surprised about the jolt on the bars lol I would think the bars would be isolated from the rest of the bike via the rubber handle bar vibration cones... the source could be from a switch/connection on the bars grounding out? I don't know, just spitballing here!

For the rest of the wiring, this thread may come in handy, a super handy wiring diagram halfway down the page by bufftester: http://www.kdxrider.net/forums/viewtopi ... am#p167527
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Re: Zapped Myself... I thought the KDX was weak?

Post by Jaguar »

I was once shocked by 12 volts while working on a boats electrical system, so yes it can happen especially if the contact metal is nice and clean.
Performance CDI -- KDX motocross mods -- the SR KDX -- expansion chamber analysis---> http://www.dragonfly75.com/moto/
seniorsehas
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Re: Zapped Myself... I thought the KDX was weak?

Post by seniorsehas »

Thanks for the links to the diagrams. I tried going through this again and hooked the yellow up to the light and grounded the negative of the light to the frame. FIred the bike up and the light came on and flickered then exploded and smoked. Apparently I suck at this. I've go three new theories.

1 The led light must be hooked up perfectly with the positive and negative. If I hook directly to a battery then reverse the polarity it won't light up. Because the power I hooked up to is AC I think that's why the light was quickly flashing and then exploded.

2My regulator is bad and too much power went to the light and blew it up.

3 Shoulda used the red wire.

What do you guys think?
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Zapped Myself... I thought the KDX was weak?

Post by pumpguy »

My vote is bad regulator. If it's good and in the circuit, it should act as a buffer and limit what goes to the lights. Use a continuity tester and ohm meter to check for good connection and regulator function.

@Jaguar would be the guy to provide the details.
seniorsehas
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Re: Zapped Myself... I thought the KDX was weak?

Post by seniorsehas »

I researched this to death. You can't run LED with AC current. You can convert with a bridge capacitor but as this bike has an unknown amount of alterations to the electrical system I'm going to go lazy, easy and a bit ghetto.

I'm gonna run my LED headlight off a 18 volt Ryobi cordless tool battery. I 've got a bunch laying around. Just gotta figure out where to hide it or "showcase" it and get a Ryobi sticker kit. jk

I did a test and it ran a 50 watt LED light very brightly for 2 hours and still had over half a charge left when I unplugged it. Wish me luck and feel free to call me a dumbass for this :boogie:
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Zapped Myself... I thought the KDX was weak?

Post by pumpguy »

Don't mean to be difficult, but my experience so far with LED tail lights and license plate bolts shows they work just fine on un-rectified 12 volt AC current. Can't say if this is true for all LED tail light bulbs, but it is true for the ones I am using.

I don't have enough time on them to comment on how long they last on AC vs DC. Also have no experience with LED headlights.

There's no question that DC current is best when using LEDs, but my experience, and many other posts on this site show that LEDs can work on AC current.
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Re: Zapped Myself... I thought the KDX was weak?

Post by Mr. Wibbens »

seniorsehas wrote:I researched this to death. You can't run LED with AC current.

Really?

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seniorsehas
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Re: Zapped Myself... I thought the KDX was weak?

Post by seniorsehas »

Mr. Wibbens wrote:
seniorsehas wrote:I researched this to death. You can't run LED with AC current.

Really?

[youtube][/youtube]
Yup. Really. Mine had the same amount of amount of smoke coming out of the light that yours has coming out the back. I know it can be done but seems unstable and you've got to burn a lot of calories to get it working. Good on you if you're into that but I'm into easy.

The mods the previous owner did are unknown and I don't want to mess with what works. The blinky r2d2 thing you've got going kinda proves the point. I've got a crazy bright light hooked up with minimal headaches and I'm enjoying it. Glad you've got whatever is good for you working.
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Re: Zapped Myself... I thought the KDX was weak?

Post by Jaguar »

LED stands for "light emitting diode"
a diode permits electrical current in one direction, not both.
so a LED can work on AC but it doesn't use both halves of the alteration of current. It is only on for 50% of the time when AC is applied but the frequency of the alterations is high enough that we don't see the LEDs blink on and off.
Performance CDI -- KDX motocross mods -- the SR KDX -- expansion chamber analysis---> http://www.dragonfly75.com/moto/
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