Ray, It is not from the gears our gear teeth are staight cut that bit of metal has a curve in it , can you see if it bends with say using 2 pair of pliers to make it bend or does it snap. I t does not look like to me that it came from a roller bearing cage either soet of looks like a bit of locating dowle not sure try the bend test. Now main jets the SR/42 ran I think smaller mains because it has more vacume at the carbies because of the bigger volume in the cylinder so sucking more fuel so they decreased the main jet size to componsate . they both run the same airbox same aircleaner and BST 33 carbs . Technically at full throttle at high revs using 117.5 mains it may loose some performance compared to the 120,s. This would burn me up inside knowing that there is extra performance for so little work .