No Spark Even With new CDI- Help Please!!


New Member
Dec 31, 2010
Oshawa Ontario
Hello all!

Was riding my bike the other day and it died slowly. After a bit of figuring I replaced the CDI ( used). It worked! Then about two weeks later and 150 kms of riding it died again very similar to how it did before. I did not notice going over bumps or anything when it died and the second time I heard a pop or bang, almost sounding like something had fallen off the bike.

Once again troubleshooting I found that the coil was bad. ie. no spark coming from the plug.

Ordered two new coils.

Installed the new coil today and rolled it forward and got a tiny blue spark. Reassembled the bike, using the same method as before. Tried to go on a ride and no spark again. I know its getting gas & air from the carb for sure.

Tried the other CDI and the exact same thing, so I would guess its not the CDI.

I tested the leads coming from the magneto ( Blue and Black) and I am receiving between -2.5 to 2.5 volts so I would guess that it is operating normally.

Any ideas or anyone else had this problem?

Thanks in advance!

Steven Gill


Active Member
Jun 2, 2010
New York
Remove the magneto and sandpaper the posts on which it sits in the engine. Also sandpaper the area around the magneto's bolt holes. You want to have a clean, shiny surface so that the magneto make good electrical contact with the engine.