Originally Posted by sailah
what about using a RC battery like a Turnigy? They are much cheaper, you can easily make up some jumper cables to jump the bike or your buddies bike.
Something like this? I have no idea if it would work but these RC batteries put out an astonishing amount of power. I don't think the amp hour really matters since the starting cycle is so short.
RC batteries lack the CCA to reliably turn a bike engine over repeatedly.
thread is quite informative on different battery technologies and their pros-cons.