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1993 Suzuki DT115 no spark to two cylinders

daleshank

New member
Hey Everyone,

Been trying to figure out the dramatic power loss I’ve been having for a while now on my 1983 DT 115. Motor was running great for a while about 42mph WOT. One outing I was at idle and I lost two cylinder and could only get up to 17mph WOT. After that I noticed the motor would start up and run great for about 10 min and then cut out.

The first thing I did was check for spark. Got spark to all cylinders. Next I checked compression, 120psi to all cylinders. Then I cleaned carbs really really good. Replaced fuel pump diaphragm. I double checked timing and it was good. Reed valves were good.

Couldn’t figure it out.

All of a sudden, I was getting the power loss conditions from the moment I started the motor.
Went to check the spark again and noticed I wasn’t getting spark on the bottom two cylinders.

I’ll be the first to say that electrical is my nemesis.

I checked Charge coil and trigger coils resistance. Trigger coils came in at 325 for both. Which is close to the bottom of the range.

I switched the leads from the CDI unit to the ignition coils and I was getting spark on the bottom two cylinders and not the top two. Which proves to me that the ignition coils are good. So now I think it’s either the CDI unit or the trigger coils. But I’m kinda stuck.

Is there a way for me to test the CDI unit?

Sorry for the long winded post, just trying to give as much info as possible.

Any input would be greatly appreciated!
 
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