[rpduc]

"Excessive" endplay seems to be normal. I'd say mine has a good 2mm. And mechanically I think it would be hard for end play to produce that clacking.

Are you sure what you're hearing isn't chain slap? I didn't believe that sound could be chainslap either but on mine it's obviously that when lugging in higher gears. I've even confused chainslap from someone else's bike with motor noise on mine. Last enduro the guy ahead of me on a transit section had horrible chainslap... we were both getting on and off throttle in such a way that I'd have sworn that noise was coming from my bike when letting off throttle, and that she was going to blow any minute... I finally got up close to him and could see his chain rattling and put 2 and 2 together.

I wonder if anyone has tried setting the chain a little on the tight side just to see if that would eliminate chain slap?? I wouldn't leave it that way, and I'm not sure if a too tight chain would stop the clacking anyway, but it might shed some light.