Gary, with the timing cover removed and the bike on it's rear stand and in gear.......if you rotate the back wheel and watch the E 80 nut that secures the half time pinion.......you will observe the nut moving and the gear not so much.........this is movement in the keyway, and this can happen for various reasons. This back lash creates a noise in the engine mostly noticeable at low engine speed that sounds bad.........The first time it happened to me on the racer back in about 2015 or 16 and I thought for a moment that the big end had gone, i have found it on other road going Vin's since then........not common but still happens. On the ESA's well another common issue that can be ignored at the time, is the actual compression of the springs........this not being enough.......Either the cam sleeve of the face washer is incorrect (perhaps a mismatch of parts used) who knows, but i have found on many bikes that when the ESA nut is tightened, that the actual compression of the springs is not enough. This must cause the springs to compress too readily causing the cam to "Ramp up" too soon. This is probably a major contributor to Vic's complaints about the design. On some engines I actually cut a piece off the cam sleeve to allow the springs to compress more, but it also depends on which washer combo you are using against these springs as well.