tapping sound when braking

[Grayo]

When I use the front brake I get an audible tap/knock coming up from the front wheel.

I had exactly the same knocking from the front end back last year. Took it to my local Yamaha dealer and it turned out to be worn front calipers. The brake pads were moving in the calipers under braking. The dealer advised me to look for a decent second hand set rather than buy new ones (extortionate price) and they would fit them for me. Managed to get hold of a near perfect set of second hand ones on ebay for £150. Problem solved.