Need electrical help on my XJ700

Hi everyone, I have a 1986 XJ700 with 36xxx miles. I bought used from a dealership in Wisconsin recently and it started immediately there and sounded great. I brought it back home a week later and started it a couple of times that day to show friends and what not. But a couple of days after that it stopped even trying to start. First I thought it was the solenoid because I shorted the solenoid and could hear the starter going, so I replaced the solenoid. After I replaced the solenoid it started right up but died after 30 seconds idling, mind you this was also after I let the battery go to a full charge on a trickle charger. After hearing how wimpy the horn was I thought maybe its a bad battery, so i bought a new duracell battery and charged it full, still nothing. I thought there was a short somewhere but sometimes it will turn on and stay on for around 10 seconds, and if there was a short It shouldn't randomly work/not work. When I hit the start the headlight fades completely away and the fuel lamp in the turns on bright red. I've looked at the schematics and have wondered if maybe it was a relay somewhere, i've already disconnected the sidestand relay and still nothing. Any input will be helpful in this stressful time of electrical issues. And its not a fuse too, just throwing that out there.

Thanks, Chief

 

I'm gonna say that it's still the battery.

 

classic poor earth symptoms.
clean up the battery terminals (on the ends of the cables too)
then clean up the earth cable ground and also check the engine to frame ground cable
stu

 

Thanks for all the input! It ended up being the ignition fuse, it wasn't broke but was not making good connections in its holder. I put a dab of solder on each blade and grinded them down a bit to get a snug fit in the loose fuse holder and vwah lag! Stressful electronic debugging over!

 

Thanks for all the input! It ended up being the ignition fuse, it wasn't broke but was not making good connections in its holder. I put a dab of solder on each blade and grinded them down a bit to get a snug fit in the loose fuse holder and vwah lag! Stressful electronic debugging over!

 

Chief, glad you found your troubles with the starting issue.

You mentioned:
"When I hit the start, the headlight fades completely away and the fuel lamp in the turns on bright red."

You need to be aware that Yamaha setup the starter switch to bypass the power to the headlight and the gauge lights when you push it in to crank the engine. And, the red "low oil" light will illuminate at the same time, verifying the self test of that circuit.

Tony

 

interesting..............