So, the other day I had the bike in the driveway and it was just idling, hadn't run in a few weeks since it's cold out... It shut off on it's own and then wouldn't restart, just the clicking of the solenoid. I put it on the charger and left it alone for a few days. Yesterday I went to start it up and all I got was one click every time I hit the button. I didn't have time to mess with it so I left it for today. Today I had the charger hooked to it, and I get the buzzing click when I hit the starter button. I checked all my connections, cleaned the ground, cleaned the connections at the solenoid, cleaned the connection at the starter. Checked my fuses, even though I didn't think those were the problem. Took my battery to NAPA and had them test it. AGM battery from AutoZone, maybe a year and a half old, tested bad. Whatever, bought a new one. Put it in, no start, only buzzing from the solenoid. Disconnect the starter cable at the starter and hit the button, now it only clicks once per time I hit the button. Just one click. Hook the cable back to the starter and I get the buzzing clicks again.
I'm really getting tired of these occasional electrical problems, usually I can fix it with a new battery, but now I can't get it to even crank. I would like to pull the starter out and test it by itself, I guess I'd have to drain the oil for that?

When I was trying to crank it and only getting the buzz, the ground wire was rather warm, but I didn't see any bare spots where it would be shorting out. I checked the starter cable and found no cracks or anything out of the ordinary there either.
What am I missing? There are only a few things to look at in the ignition system, battery, solenoid, ground, cables all good... I'd be encouraged enough if I could just get the motor to turn over
