CDI/ECU measuring scheme?

[Dutch]

Hi you all, I am new here form the Netherlands. My 2011 EC300 has no spark at this moment. Measured everything except the CDI. Does anyone know how te measure is and wat the normal Ohm readings are?

 

[Gasser Nate]

What are your peak voltage readings for the source and pick up coils (stator)?

 

[Dutch]

impulse coil = 99.7 ohm and from source is 14.5 ohm. All wel within the specs. I checked earth, cleaned it all and this is ok, all other wires are checked and ok, ignition coil to sparkplug checked and ok. so my thoughts are CDI but i need resistance figures to check.

 

[Gasser Nate]

Not resistance, but peak voltage, measuring what the stator actually outputs voltage wise. Should be at least 4 volts for the pick up and around 100v for the source coil at kicking speeds.

 

[(F5)]

Meters are great but not everything can be verified with ohm readings, cdi being one of them, the stator due to failure modes can also pass and yet still be faulty. Try AC volt tests as Nate says. Stators do fail after time. KTM style replacement.

 

[gasgasman]

+1

Can't really check resistances of transistors and diodes.
Best bet is to swap with a known good CDI module.

 

[Dutch]

Thanks for the advice. AC is very low so maybe this is the problem. I noticed that it has been onderwater and a lot of dirt has come between rotor and stator. There is also excessive play on the main bearing so i will take the engine apart first, clean rotor and stator and check again if engine is in one piece again. I will let you know what the results are.

 

[(F5)]

They do have quite a lot of play due to the bearing. My freshly rebuilt one scared me.

Electrixworld did a ktm stator which bolted onto my plate fine.

 

[Neil E.]

Can you measure the voltage output of a different bike? A KTM 2T should have similar values to a GG.

I don't know the actual voltages but it's something like: the single wnding puts out 30 volts to the CDI. The CDI puts out 300 volts to the coil. The coil puts out 30,000 volts to the spark plug.

 

[gasgasman]

If memory serves me correctly.

The CDI runs off 12v.
The CDI grounds the power to the coil, which collapses the electrical field in the coil.
Whatever voltage is required for the spark to jump the plug gap, that's the voltage the coil puts out.

 

[Gasser Nate]

If memory serves me correctly.

The CDI runs off 12v.
The CDI grounds the power to the coil, which collapses the electrical field in the coil.
Whatever voltage is required for the spark to jump the plug gap, that's the voltage the coil puts out.

That is incorrect mate, only the later ones started running off 12v Dc I believe 2014 was the changeover. Almost all Gasgas CDIs need the voltages as I mentioned earlier. They are based off Ktm/Kokusans stator.

 

[(F5)]

And RM CDI. They need that high voltage AC.

 

[Dutch]

I took the engine apart and the left hand crankbearing was gone, it had some water damage inside the bearing. Can also see that my stator had been under water so my suspicion on the stator is growing. Went through the post about a similar problem and when a take my meter i have a open yellow from the stator to the ground, it has resistance but still it is open. Could this be the problem for me not having a spark? White is also open to ground be as i understand this must be normal although the white connector coming from the stator is going nowhere on my bike for i have no battery and no regulator.

 

[Neil E.]

White wire is not used (exists for battery charging).

Yellow wire is your normal AC output for lights (has nothing to do with ignition).

The larger single winding on the stator supplies AC to the CDI (it looks different than all the other windings). If it has been soaked or corroded that is likely your problem.

The single winding (exciter coil) should measure 12.7 ohms (+/- 20%) at 20*C.

 

[Dutch]

Here is a update. After rebuilding the engine with new bearings, conrod and piston the engine sounds a lot better. Spark is back after changing the coil. The bad coil values where the same as a new coil so changing them is the only option. Kicking the engine with the bad coil gave spark bud spark was gone after some kicks so it was loosing his power. Hope that this will help other people with a simmilar problem. Keep them gassing.

 

[gg251]

What coil did you replace? Having the same problem going nuts over this.

 

[(F5)]

Replace the ignition coil with anything off a cdi bike as a test and hope you get lucky.

When stator coil fail their favourite trick is to operate just fine until they get warm in operation. Sometimes erratically which isn't as fun as if you misread that. Sometimes it will stop and restart after a while.

All good fun at the far end of the loop.

But stator replacement is easy and ktm aftermarket ones are easy to source. Just splice it into the loom way up by the airbox and use bare crimps covered by heatshrink. So few wires you cant get it wrong.