Hey there i have a gilera runner 2003 model! my batter has been working fine up until yesterday! i had my bike turned on and then turned it off again and then i turned it back on and i saw no lights t
acid overflow is caused by overheating, so there is a short someplace,disconnect the battery and neutralize the leaked acid with baking soda dissolved in water and remove the battery. (the short can even be internal, in the battery) Replace the battery with a new one,connecting a voltmeter between the negative terminal and its cable. (An ampmeter of t least 10 amps capacity would be better.) With the key off, the meter should read zero. a reading indicates a short to ground somewhere. Trace all wires, look carefully where wires go through holes or past edges for bare or burned wires. When the meter reads zero, you can turn on the ignition and gingerly touch the negative cable to the negative terminal and watch for a spark, it should be small, assuming the ignition is battery operated, not by magneto. Turn on the lights should cause a slightly larger spark. A big spark and dimming of the lights means there is still a big short you have to find. Otherwise, turn off the key , hook up the negative cable, firmly but easy to disconnect, and try the system.