Keeps blowing the main 30 fuse on my 2003 honda foreman es 450 bought new selenoid and it keeps blowing the 30 fuse and it dot start with the pullcored

 

Check you have wired the battery up the right way round. If that is OK, and the main fuse blows with ignition off, it is either the voltage regulator, check by un-plugging it, or the main thin red wires from fuse box to regulator and ignition switch. If the fuse only blows with ignition on, check when it blows, i.e. when you switch on, or when you press the start button, this tells you which circuit to check.