General Care.
Motorcycle batteries like being used. They do not like being neglected, unused or uncharged.
If left for any length of time without being charged, even if they are not connected, all lead-acid batteries will go through a natural process of self-discharging. If the battery has reached the stage of being deeply discharged it is often impossible to recover, even if the battery itself is relatively new. If the battery is connected to the bike and the bike has an alarm or immobiliser fitted the time it takes a battery to reach a deeply discharged state can be short, often a matter of days.
Regular charging is the only way to ensure a long life from your battery and work against the natural process of self-discharge. Most intelligent motorcycle battery chargers come with leads which can be permanently fixed to your battery with the battery connector neatly hidden away in the bike. Charging is then a easy matter of plugging the connector in to the charger.
It's worth noting that weather and temperature can affect the rate of discharge and functionality of the battery. Hotter temperatures rapidly accelerate the self-discharging process. However you should be careful not to let the battery go too cold as a discharged battery is less resistant to freezing. A fully charged battery would freeze around -59°C whereas a severely discharged battery can freeze at -1°C.
Cleaning.
Sulphation occurs when the lead sulphate (a white substance) is allowed to build up on the plates. It can eventually destroy your battery. To keep the battery from sulphating it's vital to check your bike is working properly, and to keep the battery terminals clean and disconnected when the bike is in storage or not being used for a long period of time. It is important that the battery is regularly charged when not in use.
Electrolyte.
The fluid in the battery is called electrolyte. It is a mixture of water and sulphuric acid that causes the chemical reaction which produces electricity. Conventional and Yumicron type batteries need to have their electrolyte checked and topped up with distilled water at regular intervals.
As part of the normal electrochemical processes of a lead acid battery water in the dilute acid is turned into gas and escapes from the cell. This needs to be replaced with either distilled or de-ionised water. Do not use tap water as this has elements which will permanently damage the battery. Once the battery has been commissioned you should never add any further acid as this will seriously degrade the life of a battery.
It is important to maintain the level of fluid as low levels can cause the acid within the battery to become too strong. This can lead to corrosion of the battery's internal components and the battery shorting itself. Maintenance free batteries use processes that quickly re-absorb the gas into the electrolyte and therefore never need topping up.