Electrical Question on a Sporty

Bike has a full charge, but when I go to start it, it clicks (very quick), then all power is gone. No lights, no neutral switch light, nada. I can wiggle the positive lead on battery and the lights come on again, but when go to starting, just the click and then its light out again.
I have had this happen twice, its been sitting as I do not wish to fry anything....relay issues?
The positive battery lead is tight as well as the ground.
ideas?

Bike was given to me from my dad, he had to give up riding after he hit the deer and telephone pole last june, which some of you may recall (not on this bike though).