honda fireblade battery keeps going flat?

Most likely a failing regulator rectifier, get a multimeter, start the bike, hold it revving at 5000rpm with the lights on Hi-beam, with a new (fully charged) battery you should have somewhere between 13.8V and 14.8V any more/less you probably have a faulty reg/rec. next check is start bike, disconnect alternator wires ( three yellow wires, (maybe a black and red too) hold bike revving (BE VERY CAREFUL WITH THIS TEST!!!!!!!!) and measure with multimeter on AC hi voltage. You should have over a 100v AC between the three yellow wires. if not it might be the alternator. From Honda you are looking at around £500 in parts (ouch!) contact westcountry windings to replace both for less than £200

Andy
August 2007