Wire connected to gas tank

Hello
I have a bit of a serious question,
What's the one wire under the gas tank near the petcock? Trying to figure stuff out before I start buying parts. I believe it is one wire. Just wondering what it is before I remove the tank and buy a replacement

 

Which bike?

 

Thought I wrote that 1985 Yamaha xj700

 

last image in the picture set on that add

 

It’s the low fuel sending unit wire.
It attaches here.

 

Yes, fuel level sensor

 

Ok next small question not as important,
Is it required on the tanks. I've seen a few aftermarket custom tanks that fit the bike but doesn't have a spot for one of those. But has a petcock.
Can I mileage my gas usage of should I use a tank for the bike or alter this one to use one

 

Without the luxury of a fuel gauge, odometers and reserve taps come into their own.

 

I'd be very skeptical with this claim.
Why are you looking for a replacement tank?

 

Old one has a lot of issues. The petcock and. Sensor are both broke and stuck to the tank. The gas cap is stuck locked and looks like there's something stuck inside it. Easier to get a new one.

 

OK, just don't throw it away. They aren't making any more.

 

Gotcha. Thanks for the help guys I appreciate