A bad ground may prevent a battery from charging completely (which will eventually ruin the battery) but it will not cause a current draw when the machine is shut off. To determine which (if not both) problem you have you have to do some testing with a a multimeter. Test the battery charge after riding/charging, in a few hours, and then after a day or two. If the voltage decreases after a day or two you have either a parasitic load or a bad battery. Do the same again, but disconnect the battery after charging. If it remains fully charged, the problem is in the machine. Bad grounds/connections are harder to test for. For that I prefer to just take them apart, clean them, and retighten them. BTW, a weak charging system that fails to charge abattery completely can ruin the battery in time, as can a charger that charges at too high a rate for too long. That can cause the lead in the battery to precipitate and fall out of the plates, or can cause sulfation. A charger like the Xtreme can be used to fight sulfation. Use of a lithium-iron battery can help prevent storage-related voltage losses that are not parasitic.