Ignition coil problem(probably)

Hello everyone,
I'm posting here for the first time because I'm looking for advice. I'll try to make it short.
So, I'm the owner of a BMW F650CS dual spark with 30000km on the clock. Currently I'm experiencing issues like stalling and stuttering and poor fuel economy which I realize could be the throttle body, fuel filter, spark plugs or ignition coils. Now, the bike had similar but not the same problems a couple years back, after which I changed the throttle body and the problem was fixed. Now I have bought 2 new elongated spark plugs, but nothing changed. Now, the fuel filter I think is not the issue because it's supposed to take much more mileage according to well, people on the internet.

So I think it's the ignition coils. Now the actual problem and my question is, how do I test which ignition coil on a single cylinder is at fault? Metering the resistance of the coils is not working, I have visually checked the insides of the caps and the main one was a bit black on the inside however after I cleaned it via WD it's still not working. I can't exchange the coils because they don't fire via the same algorithm, and I also think they may be of different specs. I couldn't find the exact information on the internet.

If anyone has any ideas, I would be extremely thankful.

Thanks in advance!

Re' checking your 2 coils.
Try disconnecting one first and then the other first to see if the engine stalls.

Thanks for the fast reply!

I mean, after I disconnect the secondary coil, the engine works practically the same, but after I disconnect the main one, it won't work... but I assumed it's normal that the engine can't run with only the secondary coil connected since the primary one is programmed to actually run the engine ?

So why do you think the engine runs just the same when you disconnect the secondary coil?

I agree, however the coil costs 1/5th of the average monthly salary of my country, so I really want to avoid buying both of them, so I thought maybe somebody has a more exact idea of how would I test them.

Thanks for your help!

OK understood.
For now, this may help https://youtu.be/x-4gJHeLdBg

This may be better
https://youtu.be/tIWpv65TmNI

I do not have spare ignition coils to test with, and the multimeter method didn't work. I couldn't get any readings from any of the coils on both primary and secondary side. I tried 2 multimeters, but maybe I should try a third one.

I had a very similar experience with a 2005 GS Dakar It turned out to be the idler solenoid in the throttle body which had sooted up, simple fix take it out clean it off and replace. Caused by overfilling the oil and it blowing back through the air filter box. Hope this helps.

It's not the idler. I even have a spare one from back when I was fixing the "impossible to diagnose" throttle body failure. I checked it out and it's fine. I even cleaned the MAF sensor and the K&N air filter. I think for the current state of the bike it can either be the throttle body again or the ignition coil. I have no idea what to do further to be honest since, as I said, everything is so incredibly costly. If I will be able to borrow a good multimeter, I'll try to recheck the resistance of the coils, but until then I am out of ideas.

Last resort is to give it to BMW service, since the last time I did that, these guys almost screwed up the whole bike in so many ways I wont even mention them.

Thanks for the reply!

It does sound like your thinking is to keep looking for a multimeter that gives you a positive reading I'd think fairly unlikely you have two faulty ones in a row, perhaps check the resistance as a dead short or even the stator windings to help know if it's reading true.

Ideally you find someone with a bike that has an identical coil to try in your bike.

If anyone knows whether the stick coil from a twin spark 1150GS is the same then I may have one which is known to be good and I could post to you as I no longer have an 1150........perhaps you can check the part numbers for the two bikes or I will when I have time.