Look at THIS THREAD.
It explains all you need to know.
Here is a LINK to one source. I believe they will ship to your door 2-3 days free of charge. There may be cheaper sources on the internet but it is close to my house so I just ride up and change battery out in the parking lot.
Search for ETX-20L

 

YOW!!!

So, now I have to worry about whether the POS Terminal is on the right or the left! ...i didn't even think of that.

Thank you for the post, RustyG. I will research further.

Robt.

 

remove air box cover. Sit on bike. Look at the battery. If the positive post (Red cover) is on the left you need ETX-20L.

 

A couple other options for the F:

DO NOT GET a Shorai LFX27L3-BS12 415 cca lithium battery. I went through two before I learned my lesson-- they're garbage.

The Antigravity ATX12-20 600cca lithium ion phosphate (LiFePO4) battery is a GREAT battery and MUCH lighter than a regular lead-acid. If you go this way, you'll also need an Optimate TM-471 lithium battery charger/maintainer and SAE connector.

R.