If your bikes charging system can charge the battery, then any standard charger should be able too as well. However, The Shorai specific charger is better, because it's supposed to charge the battery cells evenly. One big thing I did notice about the Shorai I put in my KTM, it says if it's low on a charge, that you should charge it first, before trying to start a bike, apparently you can damage the battery if you try to start it with a dead battery.
I have a Shorai charger, if you were closer I'd let you barrow it. Or you can send me the battery, and I'll hook it up and send it back when it's done.
Which one of you FF's was it?...FOUNDER!
Entia non sunt multiplicanda necessitatem