I installed a new battery on a Coolster 125 4 wheeler. Went to start it and the relay just clicks. Started fine previous to battery installation. Any idea what the problem is and what caused it?

 

Check your new battery has some charge in it. I have known new ones to be flat. If that is OK, check you have clean, tight battery connections. If it still just clicks, I go for the 12v test lamp method of checking, one wire from lamp to battery earth, the other to thick wire on solenoid that goes to starter motor. Ignition on, press start button, if the lamp lights but starter doesn't turn, you have a faulty starter. If it clicks but the lamp doesn't light, you have a faulty solenoid.

 

Not familiar with the test lamp method. Don't know much about these. I took a pair of pliers and put each end on the positive and negative terminals on solenoid and the brake lights went off. It didn't didn't try to turn over or anything. It barely even sparked. Not sure. Any help is appreciated. Like I said, I'm new to all this and don't really have much knowledge of mechanics. The atv is practically new though. Just got in December for my son and haven't really rode it much.

 

And it's more of a buzz that the solenoid makes than a click.

 

Flat battery.