90' KDX 200 AC to DC Conversion

Discussion specific to the 1989 - 1994 (E Series) KDX200 model sold in the USA
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craftman245
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90' KDX 200 AC to DC Conversion

Post by craftman245 »

Hey guys, was restoring my KDX from frame up with an engine rebuild and I was hoping one of you could give me some electrical advice. I was looking into adding a brake light in addition to the running light that comes on with the headlight. Taillight has three wires for the two bulb filments so that part isn't a problem; use the unused wire!! Ordered the tusk hydraulic brake switch for nissin brakes and wiring that in is simple but the bike's AC voltage system is a bit more tricky. From my understanding the voltage coming out of the lighting coil is much higher at idle than the 12 volts required by the bulbs; the voltage regulator keeps the voltage down in the correct range which prevents bulb burn out. The voltage regulator is after the light switch so grabbing regulated power for the brake switch would require the headlight and the running light to be on; way too many watts for that tiny stator output. So my thought is instead of moving the regulator before the switch and possibly burning it out with constant use (not to mention catching my a$$ on fire possibly), replace the OEM regulator with a Trail Tech rectifier/regulator, mount a small battery pack, and have the bike instead charge the pack while the lights run off the pack at 12 volts DC; no more flickering lights!! Problem! The Trail Tech rectifier/regulator requires a floating ground and I just don't understand how to create that! Thinking I might have to modify the lighting coil? :hmm: Thanks!
craftman245
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Re: 90' KDX 200 AC to DC Conversion

Post by craftman245 »

To answer my own question, the floating ground issue is solved by snipping off the eyelet that grounds one side of the lighting coil through the bolt that hold the coil to the plate and soldering another insulated wire to said cut wire and running that out of the engine case. This isolates the lighting coil from the common frame ground, allowing you to hook both lighting coil wires to the Trail Tech voltage rectifier/regulator.
Friedom
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Re: 90' KDX 200 AC to DC Conversion

Post by Friedom »

Thanks for posting this. I have a cheapo amazon regulator rectifier (for a China bike, I think) that I was going to wire in so I could run LEDs. Now I know I should lift the ground before I put it all back together.

"Good job, guys. "
1989KDXNH
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Re: 90' KDX 200 AC to DC Conversion

Post by 1989KDXNH »

Why cant you just pull voltage off the frame and coil wires, and rectify that voltage? You just would have to run dc ground wires.
KDXASH
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Re: 90' KDX 200 AC to DC Conversion

Post by KDXASH »

Hi I'm looking to do this mod to my 90 kdx 200 and add a trail tech dash and digital fan kit but all need DC to work dont suppose you took any pics of your wiring mods??
KDX200-E2
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Re: 90' KDX 200 AC to DC Conversion

Post by KDX200-E2 »

There are several AC/DC conversion threads that have been posted before.
Here is one I posted on about how I did it to my bike.
viewtopic.php?f=77&t=11807
I hope this links correctly.
I mounted my Trail Tech Rec/Reg isolated from the frame and ran ALL the lighting wires to
a sealed lead acid battery. Battery mounted in the rear fender bag sitting on it's side.
I used a GasGas EC model full wiring harness. It has all the hook up for a street legal bike.
I'd think most any street legal bike wiring harness would work. I used a dirt style bike as the
harness is a lot less complicated. It runs everything off the DC battery. So LED lights work fine
as I used an automotive / trailer style electronic flasher unit to replace the "thermal" style on
most bikes. So I did not need the resistor that most people use to run the LED turn signals.
I'll check back if you have anymore questions. Some research and a lot of Google'n got me
through it....Cheers.
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