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1974 DT250 wiring issues

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Replied by Gr8uncleal on topic 1974 DT250 wiring issues

Well done on identifying the problem.

You might find that the speedo and tacho illumination bulbs have blown as well. Maybe bench test them with a couple of wires direct from the battery before removing the clocks from their mounting bracket.
16 May 2021 12:18 #11

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Replied by Dberkner76 on topic 1974 DT250 wiring issues

Thank you, turns out I probably need to take some multimeter classes too.  Think I had the wrong setting which made it look like things weren’t working.   I think I have it now and found that when I rev the engine the voltage shoots up to about 18 volts!  So the regulator is the next step.  I ran out of fittings and time today.  Hoping that I can get it hooked up and tested and then get a new light going.  So close, it’s finally been nice out here so I’m really looking forward to a legal cruise!
16 May 2021 14:24 #12

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Replied by RT325 on topic 1974 DT250 wiring issues

Bummer about the headlight & hope its not a fully sealed expensive unit but might have one beam left?. Yep that regulator will save it from now on. If ya not running a battery & didn't have a regulator you could use one of the lower powered options from the lighting & charging coils "experimenting" but to get it safe at revs it'll prob be weaker than desired at low revs.

Or do what i did years ago & run a 12 volt bulb off the yellow.
Last edit: 17 May 2021 20:06 by RT325.
17 May 2021 20:05 #13

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Replied by Dberkner76 on topic 1974 DT250 wiring issues

Thought about getting a 12v light, and yes both hi and low burned out.  I thought there was something wrong with the switch when the light went out of course I switched the wrong one and both died quickly.  It wasn’t an expensive bulb, but now I’m stuck again waiting....
17 May 2021 21:04 #14

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Replied by Dberkner76 on topic 1974 DT250 wiring issues

Hopefully last question.  Am looking at the service bulletin that outlines how to wire the regulator and it mentions tapping into a dark blue wire, I only have a light blue wire.  Wouldn’t I want to tie into the yellow wire going to the headlight?  The blue wire only goes to the other bulbs which are working fine.  Just want to clear this up before I end up blowing another headlight 
21 May 2021 18:44 #15

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Replied by Gr8uncleal on topic 1974 DT250 wiring issues

The wire colours can fade (or get dirty and darken!) over time. However, as your model doesn't have a neutral light, there shouldn't be any other wires coloured a different shade of blue. 

It is the blue wire to the speedo/tacho illuminating bulbs that you splice into, not the yellow.
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21 May 2021 23:09 #16

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Replied by RT325 on topic 1974 DT250 wiring issues

If yours has the 'tail light' powered by AC like ours here then you can hook it into that blue if its easier as it goes to the other blues in the headlight. Forget that if the tail is DC powered as US models appear to be. Only mentioned it because you have a replaceable headlight bulb as ours do. But light unit could have been changed from sealed type of course.
22 May 2021 02:13 #17

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Replied by Dberkner76 on topic 1974 DT250 wiring issues

I just went with the blue wire and put a ground in the black in the headlight.  I tested the voltage and it got up to 9 with higher revs and didn’t go any higher.  It seemed much more steady.  Took it out for a test drive today for about 40 minutes and it’s still working!  Thanks to everyone for the help!
23 May 2021 13:44 #18

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Replied by Gr8uncleal on topic 1974 DT250 wiring issues

Good news and well done. 

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23 May 2021 23:45 #19

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