XJ650 Revival

So I've got her to turn over after sitting for 15 years, the battery seemed kind of weak so I hooked up a jump pack to it, tried to start and I hear a pop. Checked main fuse box and starter relay fuse and they are intact. Starter made noise all on its on while I was figuring out what happened. Apparently I chose the wrong option on the jumper. Any input on where to go next would be appreciated. Forgot to add, no lights turn on when key is switched on.

Sincerely,
Motified and slightly ashamed.

 

Get a dvm - a digital voltmeter. Learn the basics of how to use it, get a wiring diagram and start testing. Asking on here is pointless. However, I will throw this out there - every switch in the circuit, every multiple joint, or bullet joint is a source for volt drop. If you identify the supply circuits and start following along, you will quickly see that a 40 yr old loom has many potential weak points - starting at the fuses. If you want any more pointers ask - but it's 12V you need to be chasing, oh, remove clean and replace all the loom earths before starting.