Pulled head and found 1 oily combustion chamber

i have a new set of the oval ones but there are 2 circular ones that go between the case and jugs i don't have

Correction, not oval. What do your bores look like?
Steve

i think they look pretty good, I should hone regardless right? I also noticed one of my idler sprockets is missing rubber and the other is wearing down. I found some replacements that aren't quite as worn on ebay but wonder if it's necessary since some aftermarket ones i've seen have no rubber at all. I don't mind the bike being noisier if that's the rubber's only purpose. The rubber dampeners are also rock hard and I'm assuming should be replaced

They should all be replaced.
Steve

I added some picture above, I don't think there are any new options available but would like to know if here were. I've seen NOS but they are $100 a pop. Is there such a thing as refurbishing these? Is a used replacement ok?

Always give the jugs a 45* cross hatch hone so the rings will seat in. Go to Z1E and buy the Liska rollers. The ones you have will come apart in no time. I broke a cam chain that way. These will last two or three rebuilds.
Steve

Are all those components compatible with the kz650? I don't think I need the last piece do I? here is the diagram

Is it like a drive drain where I should replace the chain if I'm putting new sprockets in?

New chain would make good sense while its apart.
I would do it on my own bike
Dave

How many miles on it?
Steve

If you replace the chain you need to split the case or go with a chain link which I was talked out of doing.......... the o ring you need is 92055-101 and the oval one for the head is 92055-111 I have a KZ parts catalog I picked up on Ebay that lists the parts and numbers but Partzilla is also a good place for break downs and part numbers. And correct the last pic is for a 1000 tentioner which you don't use.

I replaced #12 with a liska and got a NOS rubber #10 off Ebay..... #4 I used over....... the 2 sprokets #5 I don't think are avaliable although I could be wrong but won't be cheap. I re use those too. (Never mind on the sprokets I see you know about them). Do Replace the #6-#7 and #2 rubber blocks and think about the #20 spring for the chain tentioner too my was way weaker than the new one and cheap.

27775 miles on it