Yes all of what you said was correct. I have a portable jumper and when I take it of the starter and negative side of the battery it cuts off

 

Could it be the rectifier. i bought a new wiring harness for it and never got to sauder it and the wires touched. its being doing it since.
no if the wires touch nothing happens.

 

The only logical explanation is it is your battery.
If nothing works until the battery is connected to the jumper then the only variable changed is the battery.

What is the Voltage you are getting on your battery?

 

Replace both regulator/ rectifier and battery. Problem fixed. Cost me around 160$

 

i got a new regulator and my battery is fine. idk what to do. any ideas.

 

Try grounding your battery. take a 8-10 gauge wire, connect to the negative post, and connect to a good chassis ground. you could test this with a jumper cable for the time being. Clamp one end to each location - neg batt post and a motor mount bolt would be a good start. See if that helps. I think the factory gound wire is connected somewhere on top of the engine block - it might be loose.

 

Here's the wiring diagram - headlight and horn are on the same side of the fuse box, the only difference is the fuse and the ground.

https://www.cyclepedia.com/manuals/o...BR600RR_03.pdf