Funny thing happened on the way to work today. About halfway there, the decible level of my engine doubled, and the vibes got crazy. I thought my muffle came loose, it was so loud, but not so much. Frame is fine, wheels are tight. rode it home, same same. My wife heard me about an 1/8th mile away. Plus on the way home it was acting like it was going to cut out on me. The revs weren't consistant. I'm wondering if maybe I might have damaged my exhaust valve. i'm running 40:1 with some sythetic oil. All I have to do is add about a half an ounce to the tank to make it 32:1. That may be to little to late. I am going to check the easy stuff first. Make sure the muffler doesn't rattle, double check the carb. The thing I don't understand is why my chain would be slacker than normal. Will check the rear axle and make sure it didn't slip, thought I don't think so. The bike runs, but it is way louder than normal and the vibes are over the top. If the vavle is shot, well, I got a back up engine I guess.