So I went to do my regular chain maintenance the other day and instead of riding it to warm the chain, I let it run on my kickstand. Doing so..exposed something I worry about. With the clutch in, the bike was fine. However, when I let go of the clutch every few seconds or go it would sputter and shake..violently. Enough that I was worried it would fall off the stand so I turned it off. Last time I did chain maintenance, this did not happen so it's something new. Another thing I noticed was there is one spot in the revolution of my rear wheel that my chain "strikes" a plastic piece. Like..a chain guard or something. It's on the swingarm. If I ride my bike slowly, say..through a parking lot, you can hear it hit that spot. A dealership is more or less out of the question since there's no such thing here and I'm not sure taking it for an hour or two roadtrip would be a good idea right now. Ideas as to what's causing the sound? Maybe the chain is too loose?