Putting a KZ1000 engine in a KZ900

Hi all, I am new to this forum and I did search for the answer to this question, but I did not find it. I am beginning a resto mod project on a 1976 KZ900 LTD, because I had this same bike when I was a teenager. The engine case is cracked on my project bike. I plan to do a lot of performance mods to the bike anyway, so I was thinking of using a KZ1000 motor instead of another KZ900. In addition to more power (I assume), I was thinking it might be easier to get KZ1000 parts since they are newer and more abundant (again I assume). I am greatly interested in any thoughts and input on this. My questions are if a KZ1000 motor will bolt right into a KZ900 frame or not, will it use the same wiring harness, and are there other issues with making this swap? thanks

Brady

Oh boy. Another unfortunate looking for cases. You are at least the 3rd. in a week. The engine cases share the same part # from '74 to at least '78. Rather than a complete engine, replacement cases would be a lot less costly. The 900 cylinders can be bored out to 1015 with the stock sleeves. Larger if new sleeves are installed. Good luck with your build.

any 73-80 900/1000 motor will bolt in,79-80 has differant charging system which is an easy fix.
major differance between 900/1000 is going to be the heavier crank in 77/78 1000 and bigger bore.
some 79-80 motors have stronger cranks and trans gears,but normally its not needed unless youre building a turbo.

That's great information--thank you. I prefer to keep the internal rotating parts lighter (i.e. the crank), so I might be better off using a bored out KZ900 motor like TomW above suggested huh? Can you still get OEM parts for these bikes also?

Depends on the parts. kawasaki.com has a parts diagram and lists parts that are discontinued. Z1Enterprises.com is a great source for parts, both OEM and aftermarket. Great service too.

Brady 154 wrote:

That's great information--thank you. I prefer to keep the internal rotating parts lighter (i.e. the crank), so I might be better off using a bored out KZ900 motor like TomW above suggested huh? Can you still get OEM parts for these bikes also?

you can probably find a 1000 motor thats rebuildable for $300- 400,then take the 900 crank and use it with 1000 topend.

Slightly off topic... So it's possible to mount a KZ1000 engine in a KZ900 frame.

Now, what would go into mounting a GPz head on that KZ1000 engine???? :ohmy: Do GPz heads fit on a "non-J-motor" without machining?

Maybe Larry can step in to answer this: If you were planning on building a runner (not a drag bike), would the cost to benefit ratio be greater to make a GPz head work, or would one be better off sending the KZ head to Larry?

by the time you buy pistons and other odds and ends to make the gpz head work id say youd be money ahead porting the stock kz head and using your stock pistons,but it depends on what youre trying to achieve.