In order to maximize the life of any sealed lead acid battery you should try to do the following:
* Always keep the battery charged.
* Avoid deep discharges of the battery.
* Use the correct charging voltage and current.
* Keep the battery temperature below room temperature.
The factor that affects life expectancy the most is operating temperature of the battery. The lower the temperature during storage the lower the corrosion rate of the battery’s internal electrical grid components.
Of course, the chemical reaction that provides starting power is temperature dependent so any battery will have less power available when cold. So storing at a lower temperature is good for the battery but it will have difficulty starting the bike over the winter.
A stored battery will self-discharge slowly. I recommend leaving the battery in place but disconnecting it from the bike to avoid any parasitic current drain. Then occasionally connect your battery conditioner to bring it up to full charge.
Granted, the cold battery won’t be as capable in starting the bike, but it’s not a good idea to be starting it during the storage period anyway.