Intermitten spark when hot..

[Daniel123]

Hi guys!

Now iam here again, but thanks to this forum and the good info here I have got my bike running several times before
A year ago i had some troubles with my bike being when hot. Ended up with changing HT-oil first and then the stator beacause of found damage to the excitng coil. Bike seemed good for a while and recently began toubleing me again after turning it off after hard riding for 25 min and impossible to start. Before that I had changed to b8es instead of br8es with resistor and that seemed to fix the bike( got really good spark and started on the first kick). This lead me to the conslusion of having to much resictance on my secondary ht-coil side making it harder for my CDI to drive a healty spark( b8es less resistance-bigger spark), but this also means there might be a lack of power to drive that circuit if the supply voltage from the exciter coil is bad due to some reason, like heat on coil causing it to short out and lowering the resistance and also the voltage supplied to the CDI?

I will check all reading again but they all seem fine. I would like to try get bike running again tomorrow and try to measure the resistance in the exciter coil and se if it is lowering when the bike gets hot. Alternativly measure the the supplied voltage while the bike is running(cold) vs varm. This problem really seem to be heat related..

So either i belivie its the exciter coil(most likely) or the CDI i getting worse and worse. But as i have red electronics often either work or not, while coils tend to have more intermittent nature espcially in hars conditions.

My question is really if it is possible to supply the CDI with 16VAC or so to test if it is the exciter coil that has been casuing all this?, because in that case the bike should start and stop easy when its hot. And if that doesnt work i can isolate the cause to the CDI

 

[Daniel123]

Did some testing today, all values seemed ok as specified in the workshop manual. Got the bike running when we push started it, verifiyng my therory about the exciter coil not putting out enough voltage to the cdi to previde a healty spark...

The exciter coil measured 15,3 ohms and i got about 10-11 volts just kicking the bike( pretty low voiltage?) Did a test by starting the bike and run it hot and stop it or untill i died by itself... What i found out by that test was the resistance went up to 25-27 ohms when it was hot..And when shut down it slowly followed the cooling down untill it was 15,3 ohms again..Seems like i have to buy a new stator again with higher voltage to provide the CDI i guess.
What stator is providing a good output voltage?

 

[Neil E.]

I would think the exicter winding specs are going to be the same whichever stator you purchase. Is the insulation on the windings discoloured like the stator has been overheated? Or is the stator dirty and corroded?

Don't forget that the flywheel magnets create the electrical energy. Has someone banged on the flywheel with a hammer? Loss of magnetism will reduce the voltage output on all the windings. Are the lighting windings delivering plenty of output (bright headlight)?

 

[Daniel123]

I would think the exicter winding specs are going to be the same whichever stator you purchase. Is the insulation on the windings discoloured like the stator has been overheated? Or is the stator dirty and corroded?

Don't forget that the flywheel magnets create the electrical energy. Has someone banged on the flywheel with a hammer? Loss of magnetism will reduce the voltage output on all the windings. Are the lighting windings delivering plenty of output (bright headlight)?

Ok, was just looking around for specs. My old stator which had a visible damage on the exciter coil might have had higher resistance.. I thinhk my old one was a 2k3 from trail tech. The stator I have now is also a 2k3 from electrex( will check tomorrow)..

Regarding the charge coils for light etc i do not use them.

Might be the flywheel losing its power but i dont think so, becasue of the low voltage output from the exciter coil and strange big variations in resistance when the bike is hot. The fact that the bike starts when pushing it over doesnt show if it is the flywheel losing power or the coil itself going bad..Only mean we need alot of spin of the flywheel for spark.
I will remove flywheel to check for damage to flywheel/stator or dirt..
What do you think?

 

[Neil E.]

It certainly sounds like an exciter winding problem. I have seen posts before about the poor quality of Electrex stators. Maybe you should look for a stock GG stator or a similar KTM unit. Can you find someone local with a GG or KTM with a 2K3 and see what their exciter winding resistance measures?

 

[Daniel123]

It certainly sounds like an exciter winding problem. I have seen posts before about the poor quality of Electrex stators. Maybe you should look for a stock GG stator or a similar KTM unit. Can you find someone local with a GG or KTM with a 2K3 and see what their exciter winding resistance measures?

Checked my stator yesterday, couldnt find any visable damage to rather than some dirt..Cleaned it and put everything back, started on the first kick. Ill guess i have to change stator to really find out if it is the stator or not..
First ill might try to measure the supplied current and voltage to the CDI and try to "replicate" the stator to see if i can eliminate the problem.
That should work i guess?
Ill add a current limiting resitor and a fuse to protect the CDI from overcurrent and try to run it hot.

 

[Neil E.]

Will the exciter coil output will be a sine wave? There will be a rise and fall that might be hard to duplicate. Don't forget about the external trigger unit. It tells the CDI when to fire.

 

[Daniel123]

Will the exciter coil output will be a sine wave? There will be a rise and fall that might be hard to duplicate. Don't forget about the external trigger unit. It tells the CDI when to fire.

Yes it will be a sine wave, but i guess that will be rectified inside the CDI anyways so DC may work aswell..The pulser coil works fine.

 

[Daniel123]

Yes it will be a sine wave, but i guess that will be rectified inside the CDI anyways so DC may work aswell..The pulser coil works fine.

Finaly made a decision of going to DC-CDI instead of buying a new original OEM stator. That way I also get a new CDI box Already have battery and rectifier.
Found a really good company, they provide all types of ignitions and etc..

This is the box iam going for!
http://www.ignitech.cz/en/vyrobky/dccdip2_race/dccdip2_race.htm

I also get the ability to program/diffrent maps and alot of other cool functions for only 180 Euros

 

[Neil E.]

Interesting product. Let us know how it works out. You could hookup your lighting coils and a rectifier/regulator to keep your battery charged.

 

[Daniel123]

Interesting product. Let us know how it works out. You could hookup your lighting coils and a rectifier/regulator to keep your battery charged.

Exactly!

 

[Daniel123]

Refreshing this thread again
Finally ordered the SPARKER DC CDI-P2 race from ignitech . Hopefully i have it on monday! I will keep you updated when i get it and starts programing it, check timing etc.

I guess 1mm BTDC (from gas gas manual) is the same as 1 degree Base advance as they say in their software to the CDI?

This will hopefully solve the suspected problem of the exciter coil heating up and stop supply power to the cdi.

 

[Daniel123]

Hi!
Got my package from ignitech in 2 days..wow Have been busy but will try to start it tomorrow with the new ignition. Done some soldering and some testing uploading ignition curves etc to the CDI. If everything works fine i will add the ather circuit component to charge the battery and my halogen lamp with the modified 2k3 stator i have
This is the circuit i will use:

 

[john r b]

Keep us posted.

 

[Daniel123]

Hi!
Got to test the ignition today! Everything work perfectly and it started very easy, first kick literally! Set up the ignition to skip one revoulution in the start to get one revultion to suck in gases and it seem work well too

Here is a vid of the first startup, sry for the bad zoom in the end..Just wanted to show you the rpm line move in the ignition curve

https://youtu.be/41FdILuR1Og

Tomorrow i will experiment with the charging circuit and hopefully get it to charg my battery!

Also some pics from today, ranked as below:
-Pic of the magneto and homemade degree wheel

-New 2k3 stator with broken eciter coil but ill will use the charging/lighting coils to charge battery so no problem.

-Old stator(not modified)electrex, still working



-Pic of the current ignition curve used

It really felt different and much more crisp then before, cant wait to test it out! The idle rpm is really low in the video(1350 ish) but i will adjust that later!

 

[Daniel123]

Took a ride today with it, oh my god what a difference! It is like a new bike, it ran really good before but now it like so much more power and it starts way too easy I can recomend doing this instead of changing stator... Totaly worth the 197 EURO for a fully two chanel programable DC-CDI unit!! That combined with a total top end rebuild with new nicasil coating(matching the new piston), refreshing of cylinder+new w?ssner piston worked out good.
I also added two switches on the aluminium radiator protector, one for the CDI(On/off) and one for the halogen lights.
Forgot the camera in the garage but will upload some pics of it later