Man! I'll have to go check my exhaust tonight and chain tonight!
I was just going to post a question very very similar to this! I'm glad I stopped to read.
I've noticed the same noise recently. On the way to work I pass through some construction that has barracades up on both sides when it comes to one lane. While I'm in there I here a "clacking/chinking" sound while under acceleration. If I'm off the throttle cruising, it's all quite. The second I roll on, I start to hear the "clacking/chinking" noise.
I'm was getting concerned about valve wear so I'm crossing my fingers it's a chain adjustment, sprocket, the after market exhaust, or just plain ol' normal.
