Hi, im new to the forum and need a little help. My 400ex will not take a charge on my new battery for more than 3 days. If I put it on the charger, It starts within a second. If its not on the charger it will attempt to start but just hums, or clicks. What could be wrong? Starter? Rectifier? Should i put in a bigger battery?

 

Check all electrical connections for any corrosion or loose connections. If you have the correct rated battery load test it even if it's new. I've had bad ones straight out of the box.You can do that with a meter. Fully charged battery should be 12.7-12.8 volts. Under a load such as cranking,voltage shouldn't drop past 9.5 volts. If it does the battery is trash.