I've had no problems with mine, but I was talking to a guy who owns a BMW dealership down the road from me who was having battery problems with his '00 model. His battery started leaking acid, which dripped out of the water-drainage hole in the plastic furniture, dripped all over the swing-arm and corroded the nuts off of it.
My two peneth-worth, buy a new battery. It won't cost you a fortune, warrantee be damned. Either the problem will go away and you'll be a happy man, or it won't in which case you can go back to the dealer, tell him it's not the battery ('cos you've got a new one) it's the bike, so FIX IT! In my experience, dealers spend money/time on a problem when they have no choice. If they think they can fob you off with a 'not my problem' response they will. (Not that I'm bitter with my dealer, he's a diamond geezer - NOT!)
The other thing it could be... Have you got an alarm system fitted? Depending on the drain that the thing sucks out of the battery, that's what could be killing the thing. If you know someone who has an ammeter, stick it in-line with the battery and see how much current is being drained when the engine isn't running. The bog-std battery is rated at 10Ah, 10 Amp hours, according to the book of words. I.E. if the current drain is 1 amp, the battery will maintain it's voltage above 12 volts (will normally be closer to 12.5/13v for a fully charged battery) for 10 hours. If a constant drain of 2 amps is being drawn, the battery will only last for 5 hours. If you've had the bike down without starting for a month, you can see that even a very small drain will kill the battery over such a long period, so you may not actually have a problem at all, just a thirsty alarm system.
All rechargable batteries, with the exception of some very expensive Lithium types found on mobile phones, have a point at which they will be damadged if they are drained too far for too long. This may be what has happened to your battery. No amount of charging will recover the beast. It looks fine when fully charged, but because it's damaged it won't hold a charge for anything but a very short period.
If you're not going to run the machine for some time, take the battery out of the bike. Keep the battery in a cool but dry spot and it will virtually last forever. Charge again before use.
[This message has been edited by Tangram (edited 05 May 2000).]
