How do you connect a scooter battery?

I have a black wire and a red wire which I know are negative and positive but I also have a 3rd wire which I guess should be connected somewhere, but where? seeing as there are only 2 terminals on the battery itself?

its possible its another live feed, dont connect that one see what happens when your main wires are connected my guess is you will find some things like ignition or lights will not work? if that's the case & you have a meter conect meter set on ohms to neg & other to the spare wire if no reading its not a neg,

the bodgers way touch the spare wire to the live briefly if no spark what ever it is thats not working on then touch wire on to live again if comes on wola

very carefully

+red wire to + on battery - black wire to - on battery, 3rd wire with fuse inline? Would go to + on battery

--Always give year, make, engine size and model # when asking questions. It's difficult to give an informed answer without that info.
--Kawasaki's use an additional wire for ground (negative), in the wire harness.
--Honda's use an additional wire to supply power to the fuse box.
--Try to determine where the wire goes to, or is coming from.
--If you have or know how to use a "multi-meter", test that wire, to see if it has continuity (has a direct connection to) either the frame or fuse box.

red & third wire to positive side of battery, black to negative side of battery