Ignition switch needs some wires & connectors replaced, and the battery was totally dry & must be replaced. A traditional lead-acid battery like the original is about $35. Depending on atmospheric conditions, they lose electrolyte through the breather tube and distilled water and acid must be added. If the fluid level or the charge drop too low, the battery is ruined. I highly recommend using a sealed battery, even though they are around $75, they last a lot longer because they don't evaporate electrolyte, hold a charge better, and often are warranted for a couple of years. When the ignition switch was bypassed and a spare battery used, I could hear the ignition solenoid go "click," which means it's working. It fired up and ran on one cylinder. Could be a new battery is all it needs for the electric starter to work, although I noticed the turn signals didn't work, and a couple of loose wires. I'd be surprised if there weren't a few other shorts. Condensers could need replacing as well, but those are cheap. Did the bike run better cold and then do worse as it warmed up? The petcock had some rusty sludge in it and wasn't draining well. I took it apart and blew some compressed air through it and it works fine now. The screen for the reserve is missing and should be fixed sooner than later, or else sediment will pile up in there again. The #2 carb seems to not be getting gas, although the float seems to be functioning.
Hotwired.
Lotsa rusty sludge.
Carb on right is dry.
No sludge!
One of the spark plugs was a extended reach plug, which caused the electrode tip come into contact with the piston head. Fortunately, this simply bent the tip of the electrode. After carb and wiring rebuild & setting all tolerances to spec, the bike fired up. It ran on both cylinders, but one kept losing spark. This was narrowed down to a short in the spark plug cable. I replaced the ignition coil and broken tail light with parts from a CB750. The battery was replaced with a sealed unit, a Power Source WP9-BS. Pulls great at 6-7k (Red line @ 10.5k!) with a wonderful throaty exhaust note - brash but not obnoxious. Suprisingly gentle clutch. Bike is beat but has a lot of life left to it and even more character.