What's the difference between KZ1000 and Z1 clutch covers?

Seller says it's different than Z1 and KZ900 covers but will still fit. It looks exactly the same to me.

The engine covers got thicker either between the Z1/KZ or the KZ900/KZ1000.  Probably to lessen mechanical noise from within, they will interchange.

Mike

900 and 1000 covers are visually the same and interchange.
As mentioned above, the later covers are thicker for sound deadening.
Only the later MK2 covers are visually different having a raised centre but again they bolt straight on too.
 

No additional comments other than I’d say look inside and see if there might still be remnants of an ink type stamp for a date. I’d keep as many dated items as possible. I’m sure either glass bead or vapor hone would remove the paint and restore the exterior finish.

This is a points cover but the clutch cover would have been stamped in the same manor.

 

To be correct the stamp would need to be

47 xx xx. The second xx will be the month and then xx will be day

example, 47 09 10 would be September 10 1972

The sprocket cover and clutch cover that came with the bike are both in very good shape... but they've been chromed.  I'll check and see if there's a date stamp.  I was thinking about sand blasting the chrome off but I don't have a blast cabinet and have recently discovered how dangerous sand blasting outside in the open air can be... very dangerous fumes that hang in the air for a very long time. I have a feeling neither one is original anyway.  If anyone would like to trade a crappy aluminum sprocket and clutch cover for some really nice chrome ones... I'd be all over that.
 

I thought I saw them as painted. Sorry. The best way to have the chrome is chemically stripped. Basically a reverse of the chrome process. Tripp Plating in Buffalo NY. 

Here’s where I pass it off the experts. I’ve seen some Z1 engines with chrome covers. I have a ‘74 engine that they are all chrome. I haven’t found anything in John Brookes book about any covers factory chrome. This is a good time to find that answer. 

Edit: If your clutch cover is original to the bike it will have S-1 cast on the inside of the cover. Also will have the ink date stamp

Engine covers on Z1s were not chrome, although some owners buff them up until they shine like chrome.  Kawasaki was cheap on chrome, which is why you can see striations in chromed wheels.  Also, look on the underside of your brake pedal, or the back side of your torque arm.  Not much chrome there.

Some later bikes had chrome covers.  My B4 has them.