Took the bike out for its weekly ride. On the way back I was still 15 miles from home and the bike developed a heavy vibration. Couldn't make it out, hard to check it while riding. Performance was not affected and the gearing seemed to be ok. Vibration increased with rpm's. Thought it might be the chain, so I started to take it easy to get home. Came to a highway stoplight and the bike died. Low idle I guess. Pushed it out of traffic and started to kick start it. Took a couple of kicks and then when it started, I heard a metal sound hit the ground. Looked down and saw a 3inch bolt? Was this from my bike? Looked underneath the gas tank and sure enough, the upper engine mount bolt was missing. Wow, must have vibrated off on the ride today. With the bolt now in my pocket, vibration was worse. Took it very slow the last few miles to get home. I'll have to get me a lock nut and replace the bolt. Interesting day.