I had a problem with my bike the other day ('99 CBR600f). I was an idiot and left the lights when I parked it in the morning, so when I was leaving work in the afternoon, the battery was as dead as. I tried to clutch start it, which worked for a while but it was misfiring all over the place and after a minute or so, it completely gave up the ghost. Took it to the bike shop who diagnosed the problem to the battery being stuffed. They put a new one in and now it goes as good as new. I was told by the mechanic however, that generally, if the battery is run completely flat, it generally means that youâ€™ll be up for a new one as this apparently stuffs up the plates permanently. This surprised me because with car batteries, you can still jump start a battery that has been run completely flat (done it many times), with usually no side effects (just means you need to take it on a long run to get the alternator to bring back up the charge again). Is a bike battery different by design (i.e. sealed unit) to a car battery that make this happen or is the mechanic telling me porky pies to boost future sales. He reckons that this will happen to a new battery as well and not just old ones. Also, I was surprised to notice the batteries ranged in price from about $60 to $240. Does anyone know what the huge discrepancy is due to (does the $240 battery actually last 4 times longer than the $60 Supercheap Auto one?).