basically the battery on my bike isnt taking a charge from the battery charger i have . and if its left it will slowly loose power. once the bike is started its fine, it takes a charge from the bike but not a charger. anyone know whats wrong?

Batterys probably dead, they can develop internal shorts that drain the battery.

Take if off the bike and note the charge with a multi-meter.

Leave it somewhere and take note of hte charge the next day.. it shouldn't have gone down by more than say .1v