Question: I just got a 2000 BMW R1100RT and the previous owner told me the battery is 7 years old so I figure it's time to go.
I saw this video <https://www.youtube.com/watch?v=XEBjekqUV9c> and the guy points out that the battery sits right next to the engine and gel batteries deal with the heat better, and the current battery is a gel battery.
I have a regular lead acid battery I was going to use (spare backup I keep around) but now I'm wondering if it's a bad idea to use it, if it's going to be right next to the engine.
Any idea?

Answer: 
A typical lead acid battery require occasional maintenance. As the battery is recharged the acid outgasses. It essentially evaporates. This gas is corrosive and an explosion hazard if it concentrated in an enclosed container. Many motorcycles utilize a covered battery box. They may also use a drain hose to remove any acid fumes out of the battery and the battery box. A gel battery can offer lower maintenance and reduced outgassing. This is important if the battery is difficult to service or subject to high temperatures where the acid is likely to evaporate quicker. So the simple answer is yes it will work providing it is of the correct size (both physical size and amp rating). It may not last as long as a gel battery and may require more frequent service. Be aware that if the battery?box does not contain a vent tube you may see some corrosion in the battery box area.
I got this from Craig Hansen of <http://www.hansensmc.com/>

Stu,

You can put in a acid battery, but most times the ABS system will fault on
cold mornings. The BMW Gel battery doesn't normally doesn't have this
issue.