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Dt 250 No spark

29 Jul 2020 08:10
CaptCove
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Dt 250 No spark #1

Hey guys, I have a 1975 DT250 I'm restoring. Wheb I got the bike the source coil was removed because the PO was going to upgrade to CDI. Andy C. gave me assistance with soldering the source coil back on correctly and where the wires go. Tested the source coil and the resistance is correct. My problem now is no spark. Power is going to the plug, it will light up a test light but no spark. The points are within .012 and .015 and the gap I believe is correct. The ignition system is work because no power in off position, making power in on position. I was wondering what else should I be checking?

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29 Jul 2020 08:15
Pedalcrazy
Open Class
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Dt 250 No spark #2
Maybe check the simplest first...a different spark plug? Can’t hurt and pretty simple.

1978 DT400E
1976 DT400C
1973 RT3
1971 RT1B

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29 Jul 2020 09:43
DEET
Moderator
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Dt 250 No spark #3

CaptCove wrote: The ignition system is work because no power in off position, making power in on position.



Where does the power come from? Kicking it over? A battery?

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29 Jul 2020 15:02
RT325
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Dt 250 No spark #4
I'm guessing its got a condenser fitted seeing things have been removed. The black from the mag loom can go direct to the plug coil to eliminate anything in between like switch etc. No battery required. Points opening & closing + contacting. Source coil not shorting somewhere. Once you have spark make sure you tighten the flywheel good & tight before starting.

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03 Aug 2020 16:23
CaptCove
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Dt 250 No spark #5
Kicking it over generates power. Tried a couple different spark plugs still nothing.

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03 Aug 2020 16:36
Pedalcrazy
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Dt 250 No spark #6

RT325 wrote: I'm guessing its got a condenser fitted seeing things have been removed. The black from the mag loom can go direct to the plug coil to eliminate anything in between like switch etc. No battery required. Points opening & closing + contacting. Source coil not shorting somewhere. Once you have spark make sure you tighten the flywheel good & tight before starting.

RT325...you always caution to tighten the flywheel but really tight. Your persistence was with me last weekend when assembling my RT1B. It made me wonder how tight? I'm not sure I've found an actual torque spec. I tightened mine to 60 ft lbs....pretty much same as primary gear on crank, clutch nut and output shaft sprocket. I didn't want to twist the end of the crank off...but I think I could have gone tighter?


1978 DT400E
1976 DT400C
1973 RT3
1971 RT1B

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03 Aug 2020 16:36
Mothersbaugh
Collector
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Dt 250 No spark #7
Have you cleaned the surface of the points by dragging 600 sandpaper or the equivalent through the points first one surface, and then the other?

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