No spark

[TRIGGER]

I have a Ktm 350sxf that is acting up. It starts and runs great for a few minutes and dies then won't start again for a few days but then starts like normal and the cycle continues. Well today I rode it until it quit then pulled the gas tank to get to the plug and sure enough I checked it and no spark(new plug). Do you guys think it's the coil, CDI box or the stator?(the spark plug boot is not cracked) I don't know how to check any of these without just replacing. I'm thinking it's the CDI box but don't know. In any case why would it not start for days then start and run fine for a few minutes and quit?

 

[Tenntrapper]

Something is getting hot and possibly expanding...maybe a cracked coil...don't know.
Should be u-tube videos about how to check each part.

 

[jlanecr500]

Likely stator

 

[Huntaholic]

My vote is coil.

 

[TRIGGER]

Likely stator

I believe you are correct. I'm not getting any juice to the coil and don't believe I'm getting any juice to the CDI box. Just got back around to tinkering with it again.

 

[Wade195]

The grounds are really important in this model.

 

[TRIGGER]

The grounds are really important in this model.

That's the first think I checked. I rode it around the yard again today and it made it about 5 or 6 laps and shut off again. It's constantly inconsistent if that makes sense.

 

[Wade195]

That's the first think I checked. I rode it around the yard again today and it made it about 5 or 6 laps and shut off again. It's constantly inconsistent if that makes sense.

That's inconsistency I'd what make me think that. Also any rubs in the wire that might be going to ground.

 

[jlanecr500]

I believe you are correct. I'm not getting any juice to the coil and don't believe I'm getting any juice to the CDI box. Just got back around to tinkering with it again.

The varnish on the stator windings is not as good or thick as was used years ago. The resistance between them decreases as they warm up and they short.