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'78 dt250 no spark

  • Vincent
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'78 dt250 no spark was created by Vincent

I ride this bike regularly, at least I did until I lost spark a few weeks ago. Now I'm stumped. Before I lost spark I replaced the points and condenser and rode the bike a few miles. I took it out a couple times tuning the carb because is wasn't running as strong as usual, then the spark faded to nothing.

I've replaced the battery, source coil, condenser (again), coil, plug, and cleaned/inspected all wire connections. 

Are my next steps rectifier and regulator? 

I'm so temped to drop the cash to convert to a modern 12v ignition. $500ish seems worth while for a bike I ride as much as this one. Recommendations?
22 Sep 2022 18:20 #1

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Replied by RT325 on topic '78 dt250 no spark

Battery has nothing to do with spark so don't worry about anything along those lines like regulator & rectifier. Start from the points & eyeball if they're opening & closing. Then look for anything shorting out like condenser wire & wires that a soldered to the condenser. Bit hard to start guessing effectively. Not just an oily plug, ok i see you've replaced it. Reading again there's nothing you haven't replaced. But was plug cap replaced or have continuity through it up in the 5k ohm range. Check that points are contacting with a meter if pos. Could shortcut the main loom & go straight from mag black to the plug coil to eliminate other possibilities in the loom & switch. I've seen an odd one where a sliver of almost invisible steel was sitting between the points terminal & to earth & that's all it took. I see it's a "78 DT250 & me thinkling DT3 for some reason but everything still applies. Think "79 went CDI.
22 Sep 2022 20:50 #2

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