KZ Motors. How many series?

Morning Folks,
I've been riding my 1100 Spectre these last two years and I suppose I've known it has a "J" motor in it. What I don't know is what makes a J motor different than the motor in my KZ 900.
I've known of a few Kawasaki KZ motor series, including the twins KZ 400, KZ 440 and the largest twin the KZ750.
I know of the four cylinder series starting from the KZ550 up through the KZ650 and finishing with the KZ 750.
Seems like the KZ 900 is closely related to the KZ1000's.
Just how many motor series exist in the KZ line?
Thanks in Advance !
Bill/KZQ

J engine went thru several iterations. Component/external coloring etc. Reasoning? 

Original 900, which became 1000, evolved into 1000 MKII, and eventually the J series (1000, 1100).  Offshoot: shaft drive variants, 1000 and 1100.  Cop bikes continued until after 2000.  A LONG life.

KZ650 was next.  Evolved into the bored out 750, with (minor) updated internals.  Further improvements, with things like a bath tube head, shaft drive, followed.  Zephyr, ZX7 variants after that.  Again, a LONG life.

KZ400/500/550 (4 cylinder) was yet another series.  More Zephyrs.  A good long life with this family here, but not as long as the other two.

KZ750 Twin.  
KZ400/440 Twin.  Less changes than the 4 cylinder bikes.
Small bore KZ's also existed.  305, 250, 300?  Not sure.  

Here is a very basic description of the different KZ1000 engines.

www.aperaceparts.com/tech/techkz1000.html
 

650 Lineage



 

Nessism wrote:

KZ750 Twin.  KZ400/440 Twin.
 
 

Do these three twins constitute a series? Do the 440 and the 400 also spin backwards?
Bill

KZQ wrote:

Nessism wrote:

KZ750 Twin.  KZ400/440 Twin.
 

 

Do these three twins constitute a series? Do the 440 and the 400 also spin backwards?
Bill

There isn't much shared between the 400 and 750 engines, other than two cylinders.  I don't know about the 400 rotation direction.  I've always felt that the 400 bikes copied a lot of elements off the Honda twins of the late '60's and early '70's.

KZQ post=913901 userid=1568
I've been riding my 1100 Spectre these last two years and I suppose I've known it has a "J" motor in it. What I don't know is what makes a J motor different than the motor in my KZ 900.
 

Speaking specifically about the "big four" engine history.  The KZ900 and 1000 engines from 1973 to 1980 are basically all the same design.  Of course Kawasaki made a whole series of running changes every year or two, some small and some substantial, but each change was an incremental update and nearly any part can interchange between any year.  

I believe the cylinder head casting was functionally the same over the whole run.  A lot of parts were made stronger (and heavier). The crankshaft got heavier between the 900 and 1000, and chaged again for the Mk2. 

The 79-80 MK2 engine had modified castings for the crank case (extra ribs) and head (added clean air ports), and a stronger crank, and I've read it had thicker engine covers to reduce noise.  But the parts are all still interchangable if you take enough of the new/old parts together (head and valve cover if using the larger cam sprockets, or the crank and generator cover and new stator/rotor, like that)

But the J engine for 1981 was basically a brand new design.  It's not the same engine at all.  It's a newly designed engine that happens to share most of the same internal dimensions with the old engine.  So it's possible to swap the transmission, or the head, with some work.  But those specific parts, and basically every other part, was redesigned from scratch for the J motor.  

The cylinder head casting is completely different, and then different again for the bathtub GPZ1100.  The cam chain system is different.  The transmission is different.  The crank case and frame mounting points are totally different.  It's a whole new design.

The Ford Cleveland and Windsor V8 are totally different designs, but I read they put Cleveland heads on a Windsor block to make the Boss 302.  That seems like a good example of how the Z1 and J motor are related.