I was riding my 2009 fxdfse2 on a hot day. I went to turn around and as I slowed into a U-turn I heard a clunking hammering noise in the primary chaincase area. I stopped and pulled over and shut it down immediately. Here is where it gets weird.... The run/stop switch was in run position and the tank switch was off. I went to restart the bike to confirm what I heard and as soon as I flipped the tank switch the bike rolled over and started....I NEVER TOUCHED THE START SWITCH ON THE BARS! The noise was still there so I call a bro and trailered it home. All works fine at home! I took off the primary cover and the starter teeth are bunged up. No metal filings in the fliud. Now the bike starts fine! I realize I should change the starter due to the teeth but I could use some advice as to... Is the starter the problem or something electrical (switch or short??) and if so how do I test it??