Thank you for the welcome, I figured I came to the right spot!
FWIW, some of you might frown on this but this engine is being built to go into a 1987 Suzuki LTR quad racer chassis. I am just helping a buddy put the motor back together to go into his chassis. He bought the whole thing has a project with the motor already in the chassis but with the top end off. He brought it to me in a box and left it up to me to figure things out. I'm not new at this but couldn't figure out where this piece went.
The bottom and was split cleaned sandblasted and assembled. The trans and crank went together with all their correct parts per the parts fish. All bearing bushings/sleeves were installed correctly the tranny shifts through all gears and doesn't have any problems. I found a chipped tooth on the primary gear so were waiting on that before we assembled the clutch and put the right side case cover back on. This is the only part I can't account for. Your help is appreciated! Unfortunately I do not have the part, instead I gave it back to the original owner to see if he could identify it with one of his other projects.