Another Mystery Part

Anyone recognize this part?



A little over an inch at the hex.

HI there, could be in the rear brake plate, inside where the cam pass through in ...........!!! may be

Looks similar the nut used to retain the valve assembly on the 1971 and on fork shuttle valves. Triumph and BSA used them. These have just some flats machined (not a full hex) that thread would be 1 3/16 diameter 20 threads per inch. The smooth I.D. suggests an interaction with a tapered dampening rod mounted at the bottom of the slider. It looks familiar and I can’t quite put my finger on it yet. Maybe it will come to me. Check the thread out and post that.