The size is a lot smaller, too, so all you have to worry about is cranking capacity and terminal placement.  Use the one they say is powerful enough for 600-700 cc motors, and that has the terminals on the same side as your current setup.

Actually,  these Antigravity batteries appeal to me because I specifically want a replacement that's of the same dimensions as the OEM.  I want to use the Ryca battery box in order to rid the moto of the stock side panels and all that other clutter.

So my question still stands: which of the Antigravity OEM replacement offerings do you guys think are direct replacement for the S40 stock brick?

If I knew what Yuasa's Suzuki Savage equivalent is I could easily answer this question, so perhaps somebody knows what the Yuasa designation is?

I recommend not getting a Shorai battery, I'm on my replacement and it still doesn't work probably in my Buell and nothing from Shorai in more than a week. Ordered a new AGM lead/acid tonight and going to junk the Shorai. Others have said the Antigravity are OK, but I decided if I am going to go with a lithium that I'll just build my own. In short for my Buell I need 4 serial and probably 3 or 4 parallel configuration. About the same price as the Antigravity, same cells, but when something doesn't work I'll have a better handle talking to the maker (me).

I know it is a lot of extra money, but I would suggest getting the 12 cell Antigravity, this is only a real 7ah battery, should provide above 300 cranking amps or better than 150 sustained high amps. These are 2.3ah cells in 4 serial configurations, the 12 cell is 3 parallel which adds to the total current available. Normal use in radio control sets these at a 30C discharge (69 amps each parallel set) and a much higher short term (start condition) peak.

I installed a shorai LFX14A2-BS12 over two years no problems and its mounted in the muffler support bracket under the bike probley more vibrations their then in the stock battery box and this battery weight less then 2lbs  Ah 14 cca 210 w/h 60 bought it at batterystuff.com

I want to use a new-tech battery like is being discussed here, because I want to dispense with the huge stock battery box and empty out all the space behind the cylinder.  For a RYCA type bike, that open look, dispensing with the side covers, is a lot cooler, methinks.  My "Double Ryca Build" buddy has already ordered his very small battery.  I think he is using a "Ballistic" brand.

If you're not ditching the factory battery-box I don't see any point in going li-ion. In fact, all I see are headaches. Regular battery chargers will ruin them, they have terrible cold-cranking abilities and they will flop around in the battery box without spacers. Li-ion batteries on cruisers are for people looking to ditch their battery box or relocate altogether.

Gyrobob wrote on 10/09/12 at 10:47:34:

Best trick of all, unplug it and take it in with you.  
and it's so small, just put it under your arm to warm it up.