Join Date: Sep 2008
Location: Honolulu, HI, USA
Or it could be something else.
Suggest to have someone sit on the bike and bounce it, while you look with a strong light up into the suspension bits. And listen for the exact location of the knock. Hint: can't see the upper end of the rear shock. You may have to get your tiny little fingers up there, but have your helper bounce gently until you know your fingers won't be squished. You may also have to remove the side fairing panels.
I'm in the middle of coil and plug replacement and the fairing side panels have to be off. Have been looking up into what's there and it's a little grimy and very close together.