I finally got around to replacing my original battery. I rode my bike about every weekend and even stuck it on a trickle charger here and there, but the battery has always seemed a little weak. Weak battery + the WR's known hard starting issues made it a good candidate for a Lithium Battery. For this model, I ordered the EXT12A Battery and the Terminal Adapter kit (you do need this). It's basically the same size as the stock battery, but a little shorter. Since the battery lays on it's side (even the stock is laying on it's side), you need to add some of the provided foam or some other filler to the portion of the battery facing the rear (about 1 inch gap). With the stuff that comes with the terminal adapter kit, it puts a metal piece up in the same spot where your OEM connectors connect to the battery terminals (facing up - what is normally the top). The issue are:
1. The new screws provided (and needed for those holes) are like 1 mm bigger or a different thread pitch and do not go through the holes on the OEM connectors.
2. The sides of the OEM connectors have bends that wrap around the battery terminal, but the EARTHX adapter is a little too fat.
So to address issue, you could cut the OEM connectors and use something else, or flatten out the side bends and ream out the hole to accept the bigger screw. I actually used a wire cutter and cut the end of the terminal which allows the ring to expand a bit (you should be able to see the snip in the pictures below) and flattened out the bends in the connector. It really didn't take much time. Also, the terminal adapter has some front facing screw holes that I believe are the same size screws as OEM. I mounted my battery all the way forward, but you could probably mount it all the way back and that should give enough room for the different orientation of the OEM wires (Looks like plenty of wire too) to use the front facing screw holes.
Here's some pics, yes, under my seat, etc. is real dirty. I ended up sticking some additional foam on the top of the battery (Where the EarthX sticker is) to snug it up a little more (Extra foam not pictured). The bike cranks a lot faster now and it seems to start better too.
Edited by mch, January 12, 2015 - 06:21 PM.