When I first joined the (not so exclusive) One Spark Club, I determined that it was the front cylinder that was playing up. The evidence was pretty convincing because after starting at a local bike meet on one cylinder and riding down the road hoping it would clear and start firing, I stopped and found that the front pipe was cold. Got home, pulled the coil out (for the first time by me in it's 18 moth life) and it was wet and rusty. Cleaned and replaced and it seemed fine. Italia Moto in Lincoln recommend red rubber grease around the seal to help keep water out, and a spray of silicone stuff (Wurth) in the cap end and in the plug. The plug on that one was on the old type, fixed to the coil.
I have since had trouble with the rear cylinder, repeatedly, and having swapped one coil under warranty I now have the new type with flying lead to the plug on the front so the plug sits around the side bhind the fairing, and the old rusty one in the rear cylinder. That is working at present. The (not so) rusty one from the rear turned out to be faulty, based on swapping the coils around and some long term tests.
Threaded Mode