Hi all.
Has anybody done any actual hands on testing of ignition coils? I looked in the CD manual but none listed and as did a search on the forum and youtube,
I have a GS911 and do not have a CEL/MIL light illuminated.
I have acquired a low mileage coil and just wondered what the correct numbers in resistance are and method to test?
Will be contacting BMW Motorrad and BMW auto dealer later on to try and see if I can get answer.
But knowing this forum is THE PLACE TO GO FIRST!

Good luck trying to get information out of a dealer. If anyone knows the answer to this it would be Duanne, he'll be around here shortly I'd imagine.

 

Afraid I'm not much help on this one... The only way check a coil is with an ohm meter. I haven't found the specified resistance of the coils we use but I've done comparisons with K1600 coils; e.g. compared resistance between good and bad coil. I don't remember the actual ohms number, but the difference was always negligible. More often than not I've seen coils seemingly check good on the bench (auto/lawn mower/etc) but fail when motor gets some heat in it.

Duane

 

You could check it cold and then warm it up in the oven and check it again, if the resistance drops, you have a bad coil.
With all the technology we have, it's still a test we do on aircraft parts!

 

A good starting point is what Duane suggested, use an ohm meter to check the DC resistance of the low voltage primary and high voltage secondary and compare those readings to a known good coil.

That takes care of the coil winding DC resistance, but more challenging is measuring the resistance of the insulation on both the low voltage and high voltage coils to ground - you'll need a Megger for that.
The breakdown of the insulation on the high voltage winding is the most common cause of failure, and typically intermittent.

To further complicate things, the insulation breakdown might only occur when its hot - you could heat the coil carefully and do the Megger test.

 

Here’s the only test that matters: if your bike runs poorly as it does when a coil is bad and the engine light comes on intermittently or always and the thrown code is bad coil, the coil is bad. Otherwise, it’s good.
As Duane says, even when a meter shows the coil should be good, your motorcycle might disagree. If it does, it doesn’t matter what your meter showed.
Add to this that, even if there was a foolproof way to test for a bad coil, the results would be good for that test and for no longer than that. There is no predicting when a coil on a K1600 will fail-Good for the test, bad before you leave your driveway after the test or for the rest of the life of the motorcycle. Either is just as likely.

 

Strange - I've been looking around for the values from BMW in relation to another thread, but can I find them........

However, this piece from Hella probably gets near - see section #4.