Headlight... I had the same issue
Funny... I had the exact same problem a few months ago. I was going through headlight bulbs as they would only last any where from one day to a week. I replaced the wire harness that goes from the headlight to the connector under the tank thinking that would do the trick, but to no avail.
Then one day I popped the seat to take a gander at the battery voltage and there was a wire coming off of the battery post that was just hanging on by one thin thread. I repaired it and haven't had any issues.
However, this wire was also causing my Speedometer to work intermittently, though that problem didn't occur until several weeks after the bulb burning out problem.
I suspect the wire, even though making a connection, would then become intermittent under the vibration, and basically was causing the light to flicker, perhaps too fast though to perceive, but enough to stress the filaments.
I'm sure you've checked all the wiring, but did you give them all a real stress test? I would not only look at them and check continuity, but would give each one a good yank and insure that they are fully connected, both in the electrical, but more importantly in the mechanical sense.
And by the way, my current headlight bucket has no rubber ring on the front, so I doubt that's your problem.
Hope I haven't beaten this to death. I was all set to directly wire the headlight to the battery, with a switch of course installed, just to rule out the EHC. Then I pop the seat, notice a poor connection, and presto... all fixed!
Okay, am I just doomed to have electrical issues, or is this an easy fix? I have replaced my headlight four times this week!:bang: I just had the EHC replaced on Saturday, and my headlight was working when I got to the dealer, but when I was leaving, the low beam poped. They were closing the doors, and I wanted to go ridding this weekend, so I took it feeling it would be an easy fix. Well four bulbs at 10-20 bucks a piece later, I getting a little pissed off. Where do I begin?