Weak and inconsistent spark - EC 300 2019

[ninetenseven]

Hi all,

I have a EC 300 2019. Was running fine, until suddenly bogged down, like i hit the killswitch. It didn't start anymore.

Noticed that with a long press on the starter button, it has a very weak and inconsistent spark.

I followed some other threads about this issue and managed to diagnose:

Coil readings OK (per manual)
Sparkplug cap OK (per manual)
Stator OK (per manual) also took it out to a visual inspection, everything looked good and healthy
Killswitch OK
Ground wiring OK
All connections are free of corrosion
All connections seem fine, with no visible issue

Now i'm leaning towards a failed CDI.

The sticker on the CDI is too worn out to read, but it should be the early version (2 maps).

Any advice or experience?

 

[(F5)]

Cdis can fail but common manufacturer for several brands if not the cdi itself.

The stator do fail. Again, a ktm generic part on early ones, can't be sure about newer ones.

A typical failure mode of all stator is works kind ok when cold. . . and insulation failure causes it to short fully when hot ending sparks. And all combinations in between.
Measurement cold then hot should see it go batty. Often. But not always obviously.

So don't discount it.

Would be great to get a swappa cdi to try but that is tricky.

 

[ninetenseven]

I agree. A stator is much more likely to go bad.

I'm leaning towards the CDI because of another thread online: https://www.thumpertalk.com/forums/topic/1403809-2018-ec300-no-spark/#comments

I have a 2019 stator, with different coloring that the 2018 workshop manual, that by default has a different stator.

One user messured his 2019 stator, and his readings were identical to mine:

I tested the red and blue and got 15.6-16.0 ohms of resistance.

Then I tested the white and grey wire together and got 96.0 ohms of resistance.

Lastly I tested the yellow to brown and got 1.0 ohms.

I tried testing the yellow to a ground on the bike and it showed an open circuit or OL.

My stator shows nearly identical values.

His problem was the CDI after all, so I am assuming mine's the same. It's very unlikely those units to fail, but giving the circumstances, same bike, same year, same problem... kinda hard to ignore.

Anyways, I sent my stator to a specialist to give it a proper test. No new CDI yet, and no backup part either.

Will update the thread once I figured it out.

​

 

[pigpen966]

I had to replace the CDI on my 19 EC 300

 

[(F5)]

Good luck.
BTW I don't know why they bother with giving measurement for coils as a meter can only really test for breaks. But stator rarely fail like that. . .. Ok occasionally.
Hopefully your specialist knows his onions.
They live in a difficult environment and they don't live forever.
Again, good luck with whatever it turns out being.

 

[ninetenseven]

Update:

Sent stator to specialist, he said it was fine. Anyway, due to some circunstances I ended up buying a new one, magneto included. No change.

Coil and cap also new. No change.

I don't know anyone with a CDI to spare for a test, so I'm ordering a new one.

Now I have a very expensive stator and magneto to spare

Will update on this.

 

[ninetenseven]

It was the killswitch plug (CDI wiring side) that was lightly corroded inside, causing a partial short.



I don't know how many hours I spent diagnosing this issue. Too many. Never suspected this one, as it is supposed to be waterproof, and tests for continuity showed it was good and there were no shorts on this plug and wires. When I removed the little silicone guard, I found a tiny spec of rust. Since I had it in my hand anyway, I might as well change it. There it is, problem solved.

A little 4mm chinesium plug burned a hole in my wallet and my self-esteem. Good grief.

 

[(F5)]

Well done. And now you have replaced the stator, which do seem to have a service life, saving you grief in 11 months time ensuring many more years of reliability.

Hope the spin makes you feel better.

Anyway, enjoy the ride.