MUSTERY LEAD WITH BUTT SPLICE

SO BEHIND THE SOLENOID THERE IS A BLACK WIRE THAT HAS A BUTT SPLICE ON IT, ANY IDEA WHERE IT GOES TO, WHEN I FOLLOWED IT, IT DISAPEARS INTO THE HARNESS,(I AIN'T BREAKING THAT DOWN, IF IIT AIN'T BROKE, DON'T FIX IT RIGHT), ANYWAY IT IS A 1979 KZ750 TWIN THAT I HAVE TO KICKSTART BECAUSE THE NEW BATTERY I GOT WON'T DO THE TRICK, MAYBE DEFECTIVE, ANY HELP WOULD BE APPRECIATED, AREN'T BLACK WIRES USUALLY GROUNDS?

Do you have a manual for your bike? How about a camera to post up what you see?
Black with a yellow stripe is KAW's ground wire for most models. If the New battery won't run the starter, what are the symptoms? Just Nothing when the button is pushed, clutch lever pulled in? Or just a click at the solenoid? Or slow to turn over?

YEAH I GOT AN ONLINE DOWNLOADED MANUAL, WHEN THE BUTTON IS PUSHED, ONLY THE SELONOID CLICKS, LIGHT WORK, JUST DOESN'T HAVE THE POWER TO TURN THE STARTER, IT'S A PRETTY NEW BATTERY, ALTHOUGH IT SAT DEAD FOR ABOUT 3 WEEKS, I'M WORKING ON A CAMERA TO POST PICS, THERE WILL BE SOME IN THE NEXT FEW DAYS.

Do you have a Volt Meter? Check the battery voltage, when the start button is pushed. Should be above 11 volts if battery is good. Check the two cables from the battery. Negative will go down to mount at the rear of the engine block. This must be clean and tight. Then the positive cable will go down to the solenoid, again clean & tight. If you suspect the solenoid, you can Jump across the two big posts with a socket extension, as it will be a lot of current/ AMPs, and see if it will turn the motor. Still checking voltage at battery to confirm it is holding a charge level high enough to supply the starter.