ya because when the sprocket comes to that location at a slow speed it grinds over it and doesnt connect. my whole quad would shake and make a big noise when it hit that area on the chain but wouldnt make a noise at high speeds. the guy that fixed it at the dealer said to never use wd-40 on chains because it wrecks the o-rings

 

chain slap on the swingarm (usually only from a kinked link, causing it to protrude lower than the rest of the chain)

 

This sounds daft but I had a noise the same as you describe and found it to be that I had over tightened the chain. Well I didn't exactly over tighten it but found that the swing arm bushings had worn and this gave some front to back movement. This meant that when I tightened the chain in the garage the swing arm was at it's most forward point. When I went out the swing arm would drop back which in turn over tightened the chain. It then snapped after getting a little air.