Lately the battery on my bike is not holding its charge too well. I endup boosting it from a car and then i can drive.  Adding distilled water helped, but only a little.

When is a time to replace the battery?  Also how long should a good battery be expected to hold its charge without riding?  Mine needs a charge after two weeks of the bike being stored in the garage (without removing the battery).  I still have the original one that came with the bike - 2002 model.  Time to replace?  If you think so, where's a good place to get one?

Thanks!

Replace it when it dies..... like now.

A battery does not last long in a discharged state.  A battery charger, used to keep the charge up, will help extend the life of the battery.  A trickle charger will help keep the battery charged when in storage.  Your battery may only need a good recharge to be good again.  Try that first, to see if it holds a good charge for a long time; if it does it's good.  If not, replace it.

 My battery croaked in my 05 at 425 kms only place I could get one was at the dealer[warranty] cost $40.00 CDN.Rumour has it that the 06 has a gell cell.   GOOD LUCK!

I just replaced my battery with a NAPA 10L-A2.  Cost about $35.  It has the vent tube on the left so I had to reroute the vent hose.

I see, thanks guys.  I guess I will try fully charging it with a charger first, rather than giving it a jump and riding for an hour or two (because that definitely doesn't hold it).  And I guess the best place would be to buy a battery somewhere locally? (Dealer?)  bikebandit.com has them for ~50 plus shipping, which seems on the high side compared to what's been mentioned here.