Just the other day, I received in the mail a new fuel tank for the 1971 Honda CB250 that I've been working on for several months on and off. I attached the fuel tank, put a little bit of gas into it, primed the fuel lines, and started the bike. It roared to life! Very exciting. So exciting that I revved the engine a couple of times and caused it to die. When I reached for the starter again, the starter button—literally the little piece of plastic that you push to activate the starter switch—crumbled and fell in pieces to the floor. The plastic was very old obviously and just gave up the ghost I guess. This presented me with a difficult situation. I could attempt to replace the innards of the switch, which would involve dismantling the control assembly and possibly parts of the throttle linkage; or I could try to hot-wire the bike and install a secondary starter switch somewhere else on the bike. I chose the former, to start, and began to dismantle the control assembly just to see if there was some easy way I could fabricate or 3D-print a new starter button and just put it in there.
The screws holding the control assembly onto the bike were very rusted. I managed to free one of them by hosing it down in WD-40 and lightly hammering a phillips head screwdriver into it, but the other one stripped immediately as the rusted head of it crumbled into dust. I tried coating the tip of my screwdriver in carbide paste and hammering it into the screw lightly, and even tried my impact driver with various phillips head bits attached. Nothing worked. So I left it there like that for a few days because I was just really busy there for a while, and came back to it today.
To get the bolt un-stuck, I first hit it with a cold metal chisel. This cut a slight V-shaped notch across the bolt head. I then fitted a carbide blade to my hacksaw and cut a deep notch, about 2/3 of the way through the head of the bolt. (I had to remove the brake master cylinder to safely access the bolt.) The notch wasn't wide enough, so I used a metal file to file out the edges of the notch wide enough to fit a screwdriver into it. I then tapped it a few times with my impact driver just to get the bolt unstuck, then unscrewed it with a flat-head screwdriver with a box wrench slipped onto the handle to give me a little more torque. Overall, it took me a full hour to get the bolt unscrewed. When I finally got it unscrewed, I opened up the control assembly and was able to easily find the contacts for the starter switch. I will soon fabricate a replacement. The entire inside of the control assembly was thickly rusted, though, which indicates to me that at some point in this bike's long life, someone left it out in the rain quite a bit.
So let that be a lesson to the kids out there. If you give even half a shit about your motorcycle, don't leave it out in the rain uncovered for long periods of time. Rust is insidious, and whenever it gains purchase inside a part, the moisture that caused it hangs around and causes more and more and more rust until there's nothing left. I now have to fabricate out of metal entirely new parts for the inside of this control assembly because some previous owner in the past 4 decades didn't care enough to throw a tarp over it. Remember, space cadets, give a shit and cover your shit.