NOOB Move - need help

I just took my wheels off to have new tires put on them and in the bucket i had the parts in had a extra part and I am not sure if it goes on the rear hub or not. I have the factory service manual and I can not see the part in any of the wheel brakedowns.i will start taking pictures rom now on.
Please help!!!

Looks like a wheel spacer probably on the sprocket side.
Steve

Kawasaki made more than 100 KZ models. They do not all use the same axle/spacer configurations. PLEASE add your bike's year and specific model to your signature line if you want the best help you can get on this site. Ed

It is in the signature line. 1982 kz750 car m1. I thought that too but it would not fit and what I ha e on there seems to have the wheel centered correctly.

That looks like the sprocket side collar. In your last photo next to the left side chain adjuster there appear to be 3 large washers where the collar would go. I can't tell if those are washers in your pic or what. ... 92027-1262

Rear brake shoes. If you don't know the age of the rear brake shoes, replace them. With old shoes a lining can separate, then get jammed between the shoe & drum, locking the rear wheel. It happened to me, so it does happen.

ps: a right-handed guy might prefer to have the castle nut on the right side.

That is where I was trying to put it but it would not fit in but I will take it apart and put it in correctly. You are right there is 2 washer and the axles adjustment nut that is turned down. I will put the castle nut on the right side. There is new brake shoes in the rear. The pads had rusted to the hub and when I took it apart it separated the shoe from the lining. I am slowly going through everything and replacing what is stuck, rusted or just looks really scary. As soon as I get some time I am going to start a build post . The bike sat up so long the rear tire was discontinued and they just started reproducing it. It is a continental mt90 16t k112.

In your pic what's to the right of the 3 big washers? Are you using a parts diagram to assemble everything?
From the diagrams at Partzilla your bike has the same rear components as my 81 650-CSR.
The oil seal is right next to the collar. Below is the only pic I have. you can see the collar, but not the oil seal.

The witness mark suggests this part goes against the bearing inside the seal.
Steve

Ref#92027A.

www.kawasaki.com/Parts/PartsDiagram/145460/1982/KZ750-M1

Thanks to everyone. I was able to get it put together correctly