Battrey won't stay charged

i'm assuming you tried charging it off the bike and it did not hold charge. i think you need a new battery. check the electrolyte level. you can open it and add distilled water if you see some of the cells empty/half empty, but all modern batteries are made "sealed", so that you buy a new one instead (you can still open most of them, it's just more work). if you do decide to open it, be carefull, it has acid inside . If all the cells are full, there might be an internal short, you'll need a new battery.

My second battery (new from KTM) is drained by both riding and letting it sit. Alternator puts out 14.3 volts, so it shouldn't be that. Bike is new and dealer still working on how to fix under warranty. Here's the thread on my problems - maybe it will help.