Opinions please. I have play in my front sprocket. Cant figure out what it is. Please watch the video and give me your opinions. Bike is in gear with rear wheel jacked up.
When I open or close the throttle I get a "donk" noise from behind the front sprocket.

https://www.youtube.com/watch?v=YoKT...ature=youtu.be

 

R U sure it`s coming from the front sprocket? From what I could tell of the video the sprocket doesn`t seem to have play in it compared to the bolt. First thing I`d check is the sprocket carrier/ driven flange on the rear wheel. do the same back and forth wiggle but observe how much play is there between the sprocket flange and the rear wheel. The cush drive rubber(s) inside the rear hub wear out and has to be changed every once in a while.

 

I don't see any excessive play in the front sprocket, that front sprocket needs changing though, you can see the wear at the bottom of the teeth. With a sprocket in that condition id lay blame on the 'hookedness' of the sprocket and damage caused to the chain to be your issue. Basically the hooked shape of the teeth hold onto the chain longer so when it pops off you hear that 'clicking' noise.