Just like he said, check the battery for the essentials. Clean connections, make sure bolts are tight and clean of corrosion if you see it. Either way unbolt the cables and take a wire brush to the contact points then put them back on. I had a Honda that the starter solenoid crapped out and I had to bridge the terminals with a steel screw driver to start the motor. If that doesn't work, smack the starter motor with a hammer or heavy screw driver. Smacking the starter will jar it enough too move the motor and brushes enough to get things to contact enough. If that is the last resort either buy and install a new brush kit or a new starter. Electrical gremlins are a pita, tracking down the problem is a pain. I like to check out the easiest solutions first. I am not an expert but I have been down this road before and was able to fix it.
05 YFZ
Custom Axis, Ars-Fx, Hiper, Rekluse, Pro-tec Skids.... Nuff Said!
OXC #317 B-Class