What are these parts from the top half of my 1981 kz250 ltd?

Just wondering what this hole is/parts to my engine. Got given the engine half apart and these were in the bin. Do they even belong on the engine I mean obviously the valve on the side does but if so the other parts where?

Picture #1 shows the rev meter drive on the cyl. head.
Picture #2 & 3 belongs to engine internals. What bike we are talking about?

From the diagrams at Partzilla:  14014-034 Positioning Plate.

1980 KZ250-D1 LTD Rocker Arms/Valves >>  www.partzilla.com/catalog/kawasaki/motor...er-arms-valves-80-d1

1981 KZ250-D2 CSR Rocker Arms/Valves >>  www.partzilla.com/catalog/kawasaki/motor...er-arms-valves-81-d2

ps: you might want to verify what model it is. I didn't see a 1981 250-Ltd at partzilla. It's listed as a csr and has electronic ignition. the 1980 Ltd has points ignition. I think the engines are essentially the same, though.
 

I'm working on a 1981 kz250 ltd but I got given it with the engine half apart:/

I think your right I just followed the word on the person that gave it to me, any idea what the thing is that isn't the rocker arm? The small bearing?

That small bearing looks like the inside part of an automatic cam chain tensioner. It grabs the shaft to keep it from backing out if the chain goes slack. There is on inside my kz1300 tensioner..

By roadhazard: That small bearing looks like the inside part of an automatic cam chain tensioner.

1981 KZ250-D2 CSR >> see retainer pic >>  www.partzilla.com/product/kawasaki/14020...64a2bd4cc80381e79ade