i have a cousin with a 2003 400 ex and his battery keeps going dead....we will charge it back up and after about a week its dead again, cant locate any shorts anywhere, could the regulator be the problem?........any information you could give me would be greatly appreciated

 

That batery sucks get a new one. I have had them go bad in 6 months. Out of 5 Hondas only one kept its stock battery more then about a year and a half.

 

his battery is only about 3 weeks old..........any other ideas?

 

Put an ohm meter on the battery, then start it up. The ohm meter should go from 12 volts to 13-14 if it doesn't then there is a problem. If it goes up it is the battery. I don't know where to start with charging problems.

My buddy bought a brand new battery used it for one ride, then on the second ride it was dead, bad battery.