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Xt 500 to 12v ?

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Hi,

My name is Ben I am 15 years old and I have been building a 1977 xt 500 into a street tracker for about six months now. I need to know what I have to to get my 6v system updated to a 12v and I also need to know if I can do it without re-wiring my stator. The only reasond I am doing this is because I was told if i dont Re-wire my bike I can't run the blinkers and taillight:banghead: I bought because they use 12v bulbs and I can't seem to find the same bulb in 6v. And yes I have tried looking for them very hard since I work at a motorcycle shop

Thanks

Ben

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  • Rewind the stator. a good shop can split a winding to give you 6v and 12v output so you don't need to change the battery and starter and regulator and...
  • Find 6v bulbs (are you talking about LEDs and 12v control circuits for them?)
  • use a rechargeable 12v battery for the blinkers and taillight.
  • Buy/build a voltage doubler for the accessories: http://www.aaroncake.net/Circuits/6-12conv.asp
  • Since the stator is 6v AC, you can build an AC voltage doubler with a couple of diodes and capacitors to run the lights: http://en.wikipedia.org/wiki/Voltage_doubler
    Use the Greinacher or bridge circuit. You can leave the existing connections alone and just wire the double in parallel with the charging output from the stator. Then feed the accessories with the 12v from the stator. You can put a 12v regulator on the output of the doubler if you need to.

Or rewind the stator if you can't find the bulbs... (yes, that was a hint)

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The weird thing is that my system will run the lights and blinkers the blinkers just don't blink and both the blinkers and taillight have 12v bulbs in them. But I was told that the blinkers are not blinking because they have 12v bulbs in them but what I don't understand is that why do they turn on but don't blink

Thanks the help is greatly appreciated

Ben

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The weird thing is that my system will run the lights and blinkers the blinkers just don't blink and both the blinkers and taillight have 12v bulbs in them. But I was told that the blinkers are not blinking because they have 12v bulbs in them but what I don't understand is that why do they turn on but don't blink

Thanks the help is greatly appreciated

Ben

Not weird at all, Ben.

A 6v 5watt bulb has 1/2 the resistance that a 12v 5watt bulb has. Thus, a 6v bulb draws twice the current that a 12v bulb does so with 12v bulbs you draw 1/2 the current using 6v that you would be if the stator was putting out 12v with 12v bulbs (that was a mouthful...). If it's a mechanical blinker, the bimetal strip in the blinker may not get hot enough to switch off and the bulbs will stay lit (albeit dimer than if they were running 12v). The faster that bimettalic strip heats up, the faster the blinkers blink. With electronic blinkers, there may simply not be enough voltage at 6v to charge the blinker circuit enough to cause it to flash.

Ohm's law proves the situation:

P (watts) = I * E, solve for I (amps) --> 5w = I*12 --> 5w/12v= 0.417 amps drawn by a 12v 5w bulb on a 12v system

Now solve for the 12v bulb resistance:

R=E/I = 12v/0.417 = 28.8 ohms

Now solve for current at 6v using a 12v bulb:

I=E/R = 6v/28.8 ohms = 0.208 amps drawn by a 12v bulb on a 6v system

You can see that you'll be drawing 1/2 the current through the blinker circuit using a 12v bulb on a 6v stator than you would be if you had a 12v bulb on a 12v stator.

So, find the right bulbs or use an auxiliary 12v battery for the blinkers, or have the stator rewound for a split 6v/12v system. There really aren't a lot of choices about what to do, but some are less expensive than others. If you have an electronic blinker, your only choice may be to run it at 12v, so trying to find 6v bulbs would be moot.

Edited by davidl9999

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Man like you said that was a mouth ful my brain hasn't sweat that much in a while but then ca schools dont have very high standards anyway all my blinkers have two wires coming out of the one ground and one hot I, wired them into the blinker wires that were already there from the stock wire g harness since this is the first xt i have build I wasn't very familiar with the wireing or wireing In General because I mostly work on dirt bikes but the wierd thing is that the blinker bulbs were two element but there was only two wires a ground and a hot the bulbs were 12v/23w/8amp and the are smaller than a trail 90 bulb I would post a picture but I don't know how. Soo all over all I guess I need some help finding some bulbs unless anybody else has another idea

Thanks a lot

Ben

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Not a problem. Are those 1157 bulbs? If so, you can just use an 1154 bulb. It's the 6v version of the 1157 and most auto stores will have them, can get them, or there's always eBay. No biggie. Here's 10 for under $9 shipped. http://cgi.ebay.com/ebaymotors/Box-10-1154-Lamp-Auto-Bulb-Automotive-Lightbulb-NEW-/110479380884?pt=Motors_Car_Truck_Parts_Accessories&hash=item19b9159194 :thumbsup:

BTW, I went to school in LAUSD, so CA schools are no excuse. :worthy:

Anyway, a little thinking isn't a bad thing. 'specially when you know something about vintage bikes that the people on the other side of the counter don't and they'll pay you to fix their stuff. :confused:

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Yea I know I love working on motorcycles. I am in the highest classes my school has to offer and the only class I don't have a A in is Spanish 1 :thumbsup: anyway the bulbs that u send me a link of are the same size as the Honda trail 90 but they are to big for what I need the only markings on the bulb were 12v/23w/8amp no other numbers if you give me your email I can send a picture because I don't know how to post one on here

Thanks for your guyses help

Ben

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PM sent.

To post a picture:

upload a photo from your PC to photobucket.com

Copy the URL of the image from photobucket.com

Click the "Insert Image" icon above the text window here.

Paste the URL you copied.

Post the message.

You should then see the image. It took me a while to get that down too.

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my 79 xt500 has a 12volt lighting system. cost was under $100.

12v halogen headlight

12v LED taillight bulb

12v regulator

30amp circuit breaker

SPST rocker switch

running the minimum for texas: no turns, no instruments, no horn.

no work to stator required. i think it was beezer joe who clued me.

its a 12vAC regulated system. super simple & i can see with a 12v halogen at night. anyone who tells you to stick with 6v lights dont ride in the dark

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Okay, that's a single filament BA15S, G6 bulb:

http://www.donsbulbs.com/cgi-bin/r/b.pl/i%7c12v%7c23w%7cba15s%7cg6%7cn-amber.html

You can use a 6v equivalent:

http://www.bulbman.com/index.php?main_page=product_bulb_info&products_id=18208

This will probably do: 6v, 10w, b6 (a little smaller globe than a g6). That will pull about the same current as a 12v 23w bulb (slighly less).

Some bulbs are available here (can't tell the wattage): http://www.jpcycles.com/bulbs?N=28005223

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