Your coils are cracked!!!

[DreamV4]

If your bike runs fine, it doesn't mean your coils are not cracked. Get a mirror on a stick and check.
I got a picture from internet to see location of parts and found crack, owner possibly didn't know about.
If you are as cheap as I am, blow cracks with heat gun to dry them and use epoxy or RTV.
this is random picture from internet, see crack:

 

[02GF74]

The plastic casing is known to develop a crack. If you look carefully, you'll see the crack follows the same line on both coils, well it did on my rear pair.

It is cosmetic and does not affect coil operation.

Like you I mixed up some JB weld (it's very dark grey) to fill the cracks.

 

[Woody]

Replace them with a coil off a Chinese scooter. No need to soder.duct tape will do the trick. I call it the Dreamv4 fix
Lmao

 

[02GF74]

The principle of operation is the same for all ignition coils but there will be differences in primary inductance and resistance which doesn't guarantee success.

If DreamV4 can get it to work, then potentially other owners can save money.

 

[DreamV4]

Replace them with a coil off a Chinese scooter. No need to soder.duct tape will do the trick. I call it the Dreamv4 fix
Lmao

spark is spark, Rolls-Royse or Chinese scooter. Chinese scooter coil had resistance 0.3 Ohm, I checked. So, your joke was not a joke. I used a coil from another car once, no big deal. My Ford Focus coils work fine so far.[/QUOTE]
Basic idea: More you know, less you pay.

 

[gentsvmax]

If your bike runs fine, it doesn't mean your coils are not cracked. Get a mirror on a stick and check.
I got a picture from internet to see location of parts and found crack, owner possibly didn't know about.
If you are as cheap as I am, blow cracks with heat gun to dry them and use epoxy or RTV.
this is random picture from internet, see crack:
View attachment 79752
[/QUOTET
Lucky you! This is a point of evolution in the life of every coil you are witnessing here.
You should celebrate this transformation by assisting with its freedom from confinement.
Free the coils by any means necessary, bolt cutters, side grinder, torch whatever.
Once freedom is granted all coils run cooler and deliver a much hotter spark, some even delivering a double spark.

 

[one2dmax]

Very common and easily fixed with some silicon or epoxy. Not a new finding by any means.