Electrical Cut-Out While Running / 82 XJ750 Maxim

So this has happened twice now, once a week ago when starting the bike after it being cold for an hour, and today at two different stoplights in Atlanta traffic (fun!).

The first time I put the key in the ignition. Dash lights up, neutral light, warning light (battery since I don't have the OEM), headlight - before I can move to hit the starter the lights go out. Nothing. I jiggle the key in the ignition - it's flickering on and off incredibly rapidly. I mess with the key and I'm not sure if what I'm doing is affecting the circuit or if there is a lone Higgs boson dancing around my bike warping space and time independent of my actions. After a lot of embarrassment I hit upon the strategy of just toggling the starter repeatedly and catching the ignition circuit on a millisecond it was actually closed. The bike started, I gave it a good bit of throttle and it settled down and idled fine from there on out. I thought it was a stray wire from the horn causing the short so I wrapped that with electrical tape and thought I'd fixed it.

Today I went for a Five Guys run up Peachtree Street - 6 lanes, no divider, plenty of Situational Awareness Practice. Leaving the burger joint I pulled onto a feeder street that would give me a green light left turn onto aforementioned homicidal traffic grid. While waiting at the light my idle was fine (1050-1100) and without a hiccup the bike stopped. Nothing on the dash, no power, nada. I fidgeted with the keys through two light cycles and had the same flickering effect, but I was never able to get it to fire. I started to back the bike backwards onto an adjacent sidewalk with the clutch in and this (by coincidence or direct action) seemed to give me enough charge to start the bike. I rode home without incident.

Back in my driveway I cannot replicate that electrical gremlin. No amount of jiggling, bouncing, or screwing with my ignition can make that problem reappear. I'll go multimeter my terminals but I'm pretty damn sure it's at or near full charge since the battery is brand new three weeks ago and my turn signal module quits blinking when the voltage gets low.

Recent changes to the bike - I've recently been futzing with the idle speed knob on the carbs (main purpose of the ride today, to get a good setting for all engine temps) after I realized it was wrong to have to ride with the choke 75% out all of the time to keep the idle above 750. I also had it cut out at another red light briefly today but I'm not sure how to classify it since it started back up immediately.

I actually used to have the same problem with a Toyota Camry . . . I realized it was a stuck EGR valve and disabled it to keep my car from randomly shutting off - though that often happened at 50MPH on the expressway.

Any thoughts? Do I need to go hunting for a short? I will admit I'm running the original fusebox as far as I can tell.

And before the Rear Drum Brake Drill Sergeant appears, yes sir, I have no signs of delamination!

Thanks guys!

 

Check and replace all original fuse panels (or newer glass fuse holders) is usually step 1 to root out and prevent electrical gremlins.

Band aid fixes while waiting for parts to arrive.

Non specifically check wire connections and corrosion.

 

Fixed it. Battery had small leeway to move and must have vibrated the connectors loose. Screwed down, done.