What's a MK II motor?

I notice that some of the KZ1000's of the late 70's/early 80's have the "MK II" motor.
What's the difference between a "standard" 1000 versus the MK II?
I think the Z1R had the MK II (squarish clutch adj cover) in 1980, but not in 1978 (teardrop clutch adj cover)?
Anybody able to elighten me with specs, etc or a place to look it up online?
Thanks in advance.

79-80 kz1000s had the mkII motor which had beefier cases and stronger crank than the 73-78 motors it also was the start of smog motor head.79 1000 ltd was a combination of left over 78 parts and newer smog motor head the 80 1000 ltd was identical to the 80 kz1000 internally im pretty sure;)

Bullit Proof would be a couple of words to describe a MarkII.
I just delivered one to Tool Texas. Seems the fellow is spending a bunch of bucks building a nice street engine for his older Kawasaki. I sold it for $400.00. It had a older style head with new valves.
I will probably get to see it when he is done.
Roy

Does this help?

The Mk II motors have a stronger crank center - they use a 16 tooth center section versus a 15 tooth center on the other Z1 KZ900 KZ1000 (thru 80) engines. Because of the crank change, the cam sprockets change from 30 tooth to 32 tooth.

The MK II engines are in the 79 KZ1000A,D & E (not the B model) and 80 KZ1000A, B, C, D, E and G models

ok new question:whistle: what is considered the cutoff point where a mkII crank is considered mandatory?

The MK II engine is also used in the 79/80 KZ1000E1/E2 ST (shaft drive) and also uses a 124 link cam chain.