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No Spark on hot wired 1977 DT250

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Can anyone tell me how to check to see if My coil/stator is making spark or if my kill switch is not functioning? At this point I'm not even sure if the wires from the Stator are routed properly to the kill switch and to the coil. It was running last year then started to sputter off and on.

Thanks!

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I have (2) '77 DT250's so i'm familiar with them.  The first place I'd start with is the points.  I think '77 was the last year for points but I've heard the CDI wasn't too reliable so I think we're better off.   Try just sliding something a little abrasive between the point surfaces and tr to clean them, but DON'T remove any material or you'll alter the timing.  If it ran before and no one messed with the wiring, it should still be OK.  If cleaning the points doesn't help, you really need a manual to check the items one by one to eliminate them.  Used parts are pretty cheap on ebay if thats any help.

I should have mentioned - have you looked at Yamahaenduro.com ?  There are some real enduro fanatics there to help out too.

Edited by motoxvet

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Thanks for the reply. I just had it in the shop $400+ ... then rode it on an MX track all day as hard as I could. It began running erradically at the end of the day... I've tried re wiring things but I have most of the wires out of the bike now. Its a 1979 nwith a 1977 engine. Points should be clean and they open and close properly behind the flywheel. I have the Digital manual but its tough to find whhat I need. Can anyone tell me what wires are essential and where they run? Kill switch, Coil And Stator wires are all I have in place. Thanks in advance I really want to ride this summer again.

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My DT's are in storage and I can't get at them for a few months..  I think you might have to shop for a '77 manual just for the ignition.  I can't even imagine the specifics of using the points instead of the CDI in your conversion..

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Thanks, I wish someone could just explain what's happening from the stator up through to spark... I know there's an Exciter coil and another coil on the Stator but I don't know how they work. There is no CDI box it was removed when we used the 77 engine inplace of the 79 motor. I have the CDI setup but they chose to use what was on the 77 motor behind the flywheel that is. I replaced the Coil (the box in the frame that has the wire to the plug).. so... and there are black wires that come off it to the kill switch. I just don't know what the current path is from the Stator up through the kill and on to the Spark plug coil. If I did I could rewire it confidently. I also don;t know how to check the stator properly using a multimeter to see if its creating electricity. The manual I have covers a bunch of years and bikes. it was bought online and is a digitized version of the old manuals. Very worth the price I paid. I also have a 1980 MX 100 with a kill switch, maybe I can trace its wires....

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