I have now changed the ignition switch on the Yamahaha. What a beast of a job!
It involved taking off the clocks (which I hate, as those bloody wires never seem to want to go back in the same place) and the top yoke. Then the fun started, as I tried to separate the old switch from the yoke. The switch is attached (heh, was attached) with two security bolts. These are designed to be tightened to a certain torque value, and then the head of the bolt is designed to snap off. So if you want to take the switch off, there's nothing to turn. David Lambert, who supplied the new switch, advised in an email to tap them round with a small chisel. Well, no chisel I have is small enough for that, and the half-inch one made no impression at all. So I attempted to drill them out. At this point I discovered that the bolts are made of the hardest substance known to Man. I wrecked two drill bits before resorting to brute force 'n' ignorance, and knocked the mounting lugs off with a cold chisel and then turned the bolts out with a pair of massive Mole grips. Surpisingly hard work.
The new switch went on without a problem, and the bike was back together in no time. I now have a lovely crisp clickety-click switch, and everything seems to be working perfectly. The slight brightening of the headlight when I touched the brake lever has gone; in fact, now the headlight dims very slightly, which is what I would expect. Road test tomorrow, assuming the rain holds off. (We're going out to the step-daughters for a meal tonight, and I need to be clean for that, so playtime has been curtailed in favour of a shower and shave.)
These security bolts are a laugh. They are meant to make it hard for a thief to remove the ignition switch and thereby steal the bike. But that, of course, is utter bollocks. The wires from the switch go to a block connector behind the headlight shroud, which is easily accessible with nothing more than popping the plastic off its lugs. If you know which wires to bridge at the connector, the bike is yours. All these bolts do is make it bloody difficult for an honest owner to carry out some basic repairs. They have been replaced with nice, simple Allen bolts. If anyone gets close enough to find that out, they will have nicked the bike already.