Z1 and KZ900

Question for someone who is well informed on the 73-75 Z1 and the 76 Kz900.

Other than down sizing the carbs from 28 to 26, are there any other changes in the engine?

Virtually no difference.

There are very minor changes in a few areas as production evolved.

The shift return spring changed in the KZ900 production run.
The idler sprocket shafts and their dampers changed during the 73 Z1 production. As did the inclusion of the o-ring channel around the cam chain area.

There are some casting changes to the crank cases and engine cases - primarily just cosmetic changes. The shift sequence on the sprocket cover, the words 'kickstarter' on the cases, the font of the 903cc changed... the fins on the head and block became more knife edged during the KZ900 production. The valve cover changed slightly.

The head nuts changed a couple of times.

I believe in '76 the carburetor tops, valve cover, stator cover, front chain cover, points cover and clutch cover all came chrome plated. Not 100% certain about that though.

How about the 5 degree difference in the ignition advance unit?

KZJOE900 wrote: I believe in '76 the carburetor tops, valve cover, stator cover, front chain cover, points cover and clutch cover all came chrome plated. Not 100% certain about that though.

They were just polished. Kawasaki had the good sense to never chrome aluminum.

Till the z1 classic

what about the crank...i have read hwere the crank got heavier...but that was yrs ago and i lost the source....i also have an article here that claims the frames(off topic :blink: ) and swing arm tubing were thicker on the green / brown kz900's

hollow cam 72 /3 ?

The Z1 and KZ900 crank are the same. It wasn't until the 1000 that the very heavy full flywheel cranks appeared.

You are correct about the cams - Z1 and some of the Z1A bikes had hollow cams. Less rotating mass, but more costly to make.

There are so many minor changes to parts during the production run that do not impact function or parts interchange across the years.

The cam chain tensioner casting changed, Kawasaki added webbing to it to strengthen it. The original valve buckets were recalled and replaced. The casting for the cylinder head originally was designed for the vacuum take-off spigots to be in the head - there was a casting to accomodate this that dropped from the head during the Z1B production run.

The raised area for the engine number changed 3 or 4 times. The early Z1's had a very short raised area with no lip around the number. Then they added a lip around it, at one point they even applied a machined pattern across the raised area to make it obvious when engine numbers were removed/changed. They then enlarged the size of the area to accomodate longer engine numbers....

To Jeff, about the original head casting.
This is a must for a total restoration on the early production Z1
if the engine has been lost, redone, blown up etc.
someone building a hybrid 73 Z from scratch.
Can you place a value on one of these heads?
Marty in Buffalo
Jeff, are you going to be open for business Monday?
I am traveling from the Finger Lakes could stop by for some parts.

Hey Jeff, have you ever thought about publishing a nice little coffee table book? I'd imagine if you advertised it as "an authoritative source for Z1 information," people would come crawling out of the woodwork to criticize and shoot you down ("No, that bolt completely hidden behind the stator cover should not, under ANY circumstances have a Phillips head") , but if you just called it a laid back book for 95% of us to read you might be able to get away with a bit less criticism.