My ignition switch has been giving me problems (key stuck, won't turn, locks up in the off position when switching to magneto, sketchy headlights, etc.). I took it apart and cleaned the contacts, then when I put it back together the lights worked great, but battery was intermittent and magneto didn't work at all.
So I'm done fooling around with it; I'm going to send it out for repair.
In the meantime I want to drive while the switch is out for repair and found what Andre and James did here: https://mtfca.com/phpBB3/viewtopic.php?f=2&t=22664
This method allows you to make this modification without disturbing the integrity of the switch wire harness.
I used a two Gardner Bender On-Off-On single pole double throw switches (get the kind with screw terminals, not spade terminals) and a new ammeter (Snyder's #A-10850-C) and adapter ring (#T-5017-D).
The wiring is simple for everybody but me, because I stink at this. Fortunately, James Doell explained it in simple terms and I managed to get it right, even though I thought I had it wrong; turns out I was wrong about that too.
Step 1
The ignition switch is wired as follows: The blue Coil wire is screwed to the center input terminal. The red Magneto wire is screwed to one of the side terminals; the two Battery wires (yellow with black tracers, one from the ammeter+ and one from the #1 firewall terminal block) to the other side terminal. Also on this battery side of the ignition switch attach a short jumper to the center input terminal of the headlight switch.
Step 2
The headlight switch is wired as follows: The jumper from the battery side of Step 1 is screwed into the center input terminal. The Dim wire is screwed into one of the side terminals, and the Bright wire is screwed into the other side terminal.
For the taillight the wire has to be split so it can be attached to both the Bright and the Dim side. I accomplished this by making two short 14 gauge "jumpers" each with ring terminals on each end. Using a 3/8 #6-32 machine screw and nut attach one end of each "jumper" to the Taillight wire and tighten the nut. Then use a large heat shrink around the connection. Or electrical tape. Whatever, just use something.
Then take the other end of each of the jumpers and screw one to the Bright side of the switch and one to the Dim side of the switch. Done.
Cutting metal is not my favorite thing to do; it's a big mess and you have to wear all kinds of special clothes, like pants and shoes. So I decided to make my switch plate out of some 1/4 inch plywood (Birch, I think) that I had on hand.
Using 1/4 thick material allows you to use the original screws and nuts (#10-32, I think) to attach the plate to the dash. I made a pattern, cut the wood, used a piece of 3/4 inch PVC for the radii on the corners, sanded, drilled two 1/2 inch holes for the switches and one 1 and 3/4 inch hole for the ammeter. The adapter ring made the ammeter easy because the meter itself is an odd size and I would've spent a long time sanding to achieve a friction fit. I attached the ammeter ring to the plate with three #6-32 slotted brass machine screws and nuts.
My plan had been to finish the wood with a few coats of Rustoleum glossy black enamel, but after the dry fit of the ammeter and switches I decided that the wood looked too good to cover with black paint, so I used three coats of Minwax Polyshades Olde Maple single step stain and polyurethane finish, which I had on hand.
I think it turned out so good I might refinish my steering wheel and Ruckstell shift knob to match!
All told I think I've got $20 or so in this.
And holy cow, everything works so well!
I just might keep this and put the repaired switch on the shelf.
And the beauty of it is that I can go back to the original switch plate by just unscrewing connections and reattaching them to the original switch. No wires were cut or otherwise befouled in this endeavor.
