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1981 XL250S 6V to 12V

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Hey everyone, want to do a 12v conversion on the bike, and have read that all that is required is to change to a 12v battery, regulator/rectifier, and then change the bulbs/flasher/horn. I have no problems with any of it except wiring the regulator in. Im pretty positive i have found the regulator up on the front of the frame, with pink, yellow, red, green, and black wires going to it. The red and black have 6V, the green is ground, and yellow the pink wires are from the stator. All the regulator/rectifiers i have found are 4 wire units, 2 from the stator, 1 from the battery positive, and 1 ground. My problem is i have two wires that have power, do i just splice the two together and then splice into the positive connection on the new regulator? Also is the regulator/rectifier one unit on this bike or are they separate? Any info is greatly appreciated.

 

i also know the stator is easily capable of 12v because with the battery out and the ignition switch out (lost the key, but just got a new one made lol) it was putting out 30v at around id guess 3000 rpms. I dont think the regulator was working since the ignition was "off".

also if anyone else has done this and knows of a 12v battery that will fit, or if the bracket can be easily modified to fit the bigger battery fill me in! Thanks.

Edited by Cp2295

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So according to this diagram if i hooked red and black together it would cause my ignition to be on all the time... Wondering if i just leave the black wire disconnected and see what happens, wondering if maybe with that system the rectifier couldnt handle that amount of load but a new full wave one could.. Guess ill just have to test and see lol

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So i got it all figured out and wanted to post my results for anyone looking at this in the future. 

As far as the battery circuit went i just removed the old 6v rectifier and replaced it with a 12v 4 wire. 2 wires went to the magneto (yellow and pink wires), 1 to the battery positive (red wire) and one to negative (green wire), i left the black wire (just snipped and taped off). Then i changed all the bulbs, the horn and the flasher. The battery i used was a duracell 12v that i got at batteries plus bulbs, fits tight but works just fine, its an agm btw i will post the part number later. I opted for led bulbs and flasher so it wouldnt drain my battery so fast. One thing to note is that the 6v wiring to the turn signal indicator bulb is insane. One wire goes the the center of the bulb for left turn signal and the other goes to the outside-which is always negative i had thought, from the right side turn signal.. So i had to use the original indicator bulb for the left turn signal and the high beam indicator for the right turn signal, and then ground the left turn signal indicator bulb. Not ideal but it works. All 4 bulbs will flash if you dont do this. 

 

As far as the headlight i heated up the solder around the base of the bulb and then broke out the glass to remove the 6v bulb. Then i put a 9145 bulb in there and put another o ring below the red o ring and super glued it in there, fits nice and tight. The 9145 bulb is a single filament so unfortunately theres no high beam option, maybe someone else knows of a dual filament bulb thats the same size, but it is plenty bright so not an issue for me. Then i put a 12v regulator in line with the power source, no need for a rectifier here since i used a halogen bulb. It is 12v AC. I could not get a rectifier to hook up for whatever reason it just wasnt working so i got a moose racing 12v regulator. Just hook the yellow wire inline with the headlight power wire and then ground the black wire on the regulator, easy enough. 

 

so far ive had no issues and my lighting is much better!

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Funny!  I am doing the same thing to my 1980 xl500s and was confused until I found your very new post (about 20 hours old!).  The other posts floating around the web (going back to around 2002) aren't nearly as clear as your write-up.  Thanks for the info!  So, I am assuming you haven't touched the 6v ignition circuit, correct?  Also, what reg/rec did you use for the battery circuit?  

Cheers,

gg

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Glad i could help someone so quickly! Anyways i just grabbed a cheap ebay reg/rectifier, just get the 4 wire one. I did not touch the ignition system at all. Let me know if you got any more questions!

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