1978 ATC90 lighting question

[ajjeepspeed]

Hey everyone, first time here. I have had an atc90 for years and have taken it all around the country to offroad races, it's the perfect pit bike. My question is that I have a few KC Highlights Pro 6 Led's laying around and I would like to replace the stock headlight with one. What exactly do I need to do to accomplish that? I have read numerous forums but have yet to see a definative answer. I have a full fabrication and machine shop and not really worried about spending some money. Is it possible? I never have to work on this thing so I dont know much about them. There is.no shops in southern california that are very knowledgeable with them.

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[shortline10]

The lightning system is only 6 volts with no regulator so probably not doable .

[coolpool]

Or you squirrel away a 12v battery into the frame (hollow) and recharge manually as required. I think that would work?

[ps2fixer]

Another option could be to get an aftermarket alternator that runs at 12v and is higher output than stock. Of course you'd likely want to run a voltage regulator and assuming it's a points engine you might have to switch to a 12v coil instead of 6v. The ATC90's aren't my strongest model for knowledge.

I've heard nothing but good about this site, but have no personal experience with them. I'd say to contact them though and see what they suggest. They have atc110 and up stators, but no 90s or 70s for some reason.
http://www.rickystator.com/product/stators/honda?page=1

[jb2wheels]

I'd plug one in, start the trike and see if it works. Just plug into the tail light plug as a test.
If so, add a 2-wire regulator (shunt).

I've had good luck running LEDs on stock systems on a couple of ATC70s and TRX70s and a Tecate using stock lighting system with the addition of a 2-wire regulator like this: https://www.motosport.com/trail-tech...tage-regulator

(editorial comment) I believe the AC lighting system doesn't care 12V or 6V.

I also run smaller LEDs (6 bulb 18W cubes) on my 250R and 350X stock lighting systems (they have regulators) with no changes.

The only problem I've had is running the big 72W light bar on my 350X. I could not get it to work reliably. This might have been a problem with the switch I found later when my lights would shut off randomly when riding at night...
Before fixing the switch, I added an AC to DC converter like this to the LED: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I run the LED with this converter and the stock headlights at the same time with no issues.

(editorial comment) The 72W light bar puts out a lot of light and looks cool, but something about the pattern leaves me a little "meh" in the sand dunes at night. Going to try an HID on my WR450 conversion.

[ps2fixer]

Lighting in the old sense doesn't care about voltage, but a 6v bulb is made and speced correctly for 6v, if a 12v bulb is ran on 6v it will be dim.

LED lighting on the other hand is all about specs, LEDs when properly built requires a current driver, so it accepts a voltage input range, too high and it burns out the current driver, too low and it can flash and do other funky things. Wattage is another huge factor. If the alternator makes 50w but you try to draw 70w it will be under voltage and possibly overheat your alternator.

Some machines have a voltage regulator, others use the bulb draw to use all the power it's creating. LED's are much more efficient power wise, so in most cases you'll want to add a voltage regulator if your machine doesn't have one already for LEDs.

Just to jump on the 350x example, the alternator max output is 200w @ 5000 rpm, it doesn't give an idle output so I'm not sure what it would be putting out, but my guess is it correlates with rpm fairly well, so 1400rpm vs 5000rpm would end up being 71w. Most LED lights are rated for what the LED's use power wise, and it omits what the current driver needs (~10-15% more), so you need a min of around 83w for only the 72w light bar to work right. In this case, best results would be had if you installed a battery and wired in a diode to act as a rectifier (forcing the ac into a dc like power that the battery can charge of of). When the machine idles, it would use the excess power it needs for lights from the battery, and when you're driving the machine, the excess power generated would be stored in the battery.

Another note, most AC to DC converters would use around 10-20% power to convert as well, unless it's a high efficiency switching power supply like a computer or laptop uses.

Anyway, back to the ATC90 talk, the headlight is 6v 15w, and taillight is 6v 3w, so my guess is the alternator generates around 25-30w max. I didn't see the mention of LED in the first post so I was purely looking at 6v vs 12v and the fact the ATC90 probably doesn't generate enough power for large aftermarket lights. You'd need to find the power specs to see if the min voltage is 6v or less and what the power draw is.

LEDs are very easy upgrade for any machine with a voltage regulator stock like any one of them with a battery/electric start, just match the LED light wattage to the stock headlight bulb wattage and you're pretty much set.

FYI, 6v vs 12v makes a huge difference in amps when talking electrical, however wattage is basically the universal term for power talk, 12w @ 6v = 12w @ 12v for raw power usage, difference is the 6v has 2amps of flow while the 12v has 1amp of flow.

With the LED talk is also the color of the LED, Yellowish/natural lighting is most power efficient and you can see things well, the whiter/violet light makes it seems brighter but things blend in more, however reflective surfaces are blinding. I'd suggest around 3000k-4500k, I light my house with 2700k and it looks the same as the old school 100w light bulbs, so everything is slightly yellow. My dad uses 3000k in his house and it's quite similar to the florescent lights he replaced (the long tube style like stores used to use), I think they are around 4000-4500k.

Edit: Hopefully it didn't sound like I was attacking anyone or being a jerk, just typed this up real quick cuz dinner is done lol.