1986 Honda Shadow VT700C electric problems?

1986 Honda Shadow VT700C electric problems? - 1

Added (1). I bought this bike about a month ago, and right off there was trouble with the turn signals. Fixed it, no problem. It runs rough. It used to run ok, but now it just won't start. I think the spark plugs aren't hitting it off right, and it has 4 of them. So, that points to the ignition coils, black box and/or battery, I think. Another note, the tachometer sometimes goes insane. Turn the key, and it jumps up to 8 grand, bike not started. The tach is connected to one of the coils. Possible lead?

Added (2). More goodies:
Bike has 80,000+ miles on it. Carbs were redone, but doesn't entirely eliminate the possibility of carb troubles. When it was running, it ran rough. Have to let it warm up a little bit before it goes to idling rpm, usually under 1,000. When it's hot, idles above 1,000. On the road, it's fine when once it's warmed up. But if you were to get on the throttle, it'll bog down a little bit before hitting it off, like it would have too much or too little gas.

Burn it

Can you give a little less detail? Probably something electrical is all I got with no details.

Good job with the details - Have a look at the plugs to see if they are dry or wet after failing to start (just one per cylinder is fine). While you are messing around with the plugs make sure you have a hot blue spark. If dry you are not getting fuel - either because the choke enrichment valve is not functioning or the fuel bowl is empty (fuel pump issue possibly). You should be able to pull the drain on the bowl to see if it has fuel. Once you are certain it is a fueling issue or ignition time to go to the next step. Do you know if the carb rebuild included a new diaphragms (there's some age on them) - a cracked or holed diaphragm can cause all kinds of issues too?

Time to pull the covers, tank, seat and battery and unwrap and run through the harness looking for weirdness. Look for rubbed-off insulation. Check every ground. Disconnect all of the connectors and clean and check every pin for being burned or partially pushed out. An old bike can have multiple electrical problems. In the alternative, you can install a couple dozen voltage data loggers throughout the electrical system, if you know how to interpret the data. But it really is easier just to look. When were the spark plug cables changed? When were the battery ground and starter cables changed? Never? Oops. No maintenace of the electrical system = no maintenace of the electrical system. Electrical stuff corrodes, gets intermittent, and then gets pretty strange.