Z1 vs. KZ

Just wondering why Kawasaki dropped the Z1 after 1975 and went to the KZ900. Also wondering what the difference is between the Z1 and the KZ line.

Any ideas?

from what i have heard the Z1 was faster than the kz , but i dont know. My dad said he raced a buddy of his who had a kz 900, and beat it. I dont know why kawasaki dropped the Z1 after 75

According to Marsden in Original Kawasaki, Kaw changed their identification method for all bikes in 1976. KT indicated Kawasaki Trail, KE was Kawasaki Enduro, etc. Kaw was so proud of the Z line, that the just made it KZ (Marsden's theory, anyway).
There were changes make in the KZs, most significantly maybe the carbs. Smaller 26mm Mikunis were used in 1976.

i guess that makes sense if they were changing there id method, and i forgot about them going to 26mm mikuni's

Post edited by: oldkaws4ever, at: 2007/06/25 15:25

Remeber, the KZ designation only applies to North America...in all other areas the bike was called Z900, Z1000, etc. etc.

They went to the 26s from the VM28SC because those carbs had very crude sync mechanisms. The VM28s on the 73/74 were perhaps capable of delivering more air/fuel than any other Z/KZ VM series carb but they were (and still are) somewhat tricky to tune and synchronize. The VM26 carb is a lot more user friendly. The 76 sync mechanism is unique to that carb (and the 77 KZ900A4 and LTD model) and the VM29 smoothbore... all share the same sync. They went to a much simpler mechanism with the 77 KZ1000 models and used that sync mechanism through the 80 (well 81 cop bike) versions of the VM carbs.

As far as which bike was fastest, I suspect the 73/74 Z1 and Z1A were faster than a KZ900 but the KZ900 had frame beef-ups that made it a whole lot less scary to ride and made about 95 percent of the power the early Z1 did... the KZ900 is actually quicker and has more torque down low where the early Z1/Z1A carbs kick in where the cams come on profile; at about 7K rpm. Problem with any of the factory carbs is that the fuel rails or the pipes carrying fuel are just too darn small... the VM29 smoothbores solved this problem by having bigger internal pipes to carry fuel. They would not run out of gas even on a modified engine where the stockers will. The little fuel pipes on a stocker are less than 1/8" diameter and the VM29 is probably more like 1/4" diameter. Plus the 29s have the fancy slide blocks that are supposed to help atomize gas...

In 1976/77 the Z1 grew to 1000cc. The crankshaft had 3kg (6.6lb) added to increase flywheel inertia by making the crank counterweights full circle. This smoothed out the engine but made it more reluctant to rev freely.

The early Z1's probably were the fastest of the 900's.

They were slightly lighter - including running non o-ring 630 chain, lighter front sprocket (and even had hollow cams) which effects HP at the rear wheel.

The 4-4 pipes on the Z1's were less restrictive than the KZ900 '76' pipes.

Cool! gues my choice of the '74 Z1 900 was a good one:whistle:

z1rick wrote:

Cool! gues my choice of the '74 Z1 900 was a good one:whistle:

It was a GREAT one! But I'm a little biased too:whistle:
Pat

My friend had a stock 1975 900 that was
one of the fastest stockers around.I just
barely beat him with my 1977 KZ1000 when
I bought it.We both got beat by a XS1100
in 78 and then started hopping them up.

This guy's got some interesting info on the progression from Z1 to KZ here. www.classicbikes.co.uk/machine.html