A million thanks to the information on this and another thread or two, I spent last evening taking apart , cleaning and reassembling the starter switch due to the same intermittent headlight issue.
Unfortunately, the solution didn't seem to be something a simple cleaning and buffing of contacts would cure. The contacts did look a bit worn, but not unduly, and not unduly dirty either. Certainly there was no evidence of burning or melted bits that some have reported. All was buffed clean, sprayed with contact cleaner, and dried before reassembly, but still no joy. In fact, there was no power getting through the switch at all. The lights could be made to flicker with some wiggling of the switch though, so problem still lay within the switch and not one of the other connectors in the fairing.
Turns out that with the main housing apart, I could squeeze the plastic cover over the contacts and it would work fine. The little contact nubs that slide across the contact points seem to have worn enough that they wouldn't make good contact any more. Squeezing the cover puts enough pressure to establish good contact. Solution: -Found a bit of foam weather-stripping and slipped it under the aft part of the white plastic cover, (clear of the wiring), before installing it over the switch contacts. It should help squeeze the two parts of the switch together. This was better, but not quite enough to keep the contact consistently reliable. Another bit of weather-stripping added to the underside of the handlebar before reinstalling the lower half of the outer housing put enough pressure on the switch inside and all seems good.
Now I am left with another concern. The problem with the switch appears to be from wear. As the copper contacts wear, (or maybe its the plastic parts), the fit gets sloppy and headlight/starting problems appear. Applying a bit of extra pressure to the switch assembly may fix the problem for now, but I fear the contacts will just continue to wear down with use and before long the entire thing will need to be replaced. Admittedly, it has taken 6 seasons for problems to appear, but with the extra pressure and friction now on those contacts from the added bits of weather-stripping, I doubt it will take another 6 years for the problem to start up again.
Can we buy only the push-button portion of the switch with the raised nub contacts and if anyone has done this, did it solve the problem? Parts fiches only show the whole assembly that is fixed to the handlebar. Seems crazy to have to buy all that, just to deal with a couple of interior bits.
Oh, and before the suggestions to get the Eastern Beaver fix come in; I am still considering it, but the electrical load through the switch doesn't seem to be the issue at this point, so I donít think it would do anything to fix this particular problem. The switch will still wear(out), from the sliding action. Seems like it isn't the best design to me.