kz1000 internals in z1 cases

Are there any issues with installing kz1000 internals in z1 cases? Essentially, I want to use the internals from a kz1000 engine that I have, with 900 jugs bored to accept the 1000 pistons, along with the 1000 head (the 900 head I have is cracked).

I will mate this Frankenstein motor with the 73 z1 carbs. I'm trying to build a sort of correct looking engine with parts that I have on hand. My gut says that mating the 1000 internals with the bigger z1 carbs should produce a really nice engine with smooth tractable power. I have yet to decide whether or not to put 6mm inserts into the 8mm exhaust stud holes. I'd like it to look, at a glance, like an original engine.

Any issues with the 1000 internals? Any issues with boring the 900 jugs that big? Any carb jetting issues? Any other thoughts?

Cheers,
Ross

Read this and then ask them:
www.aperaceparts.com/tech/techkz1000.html

Nope! I have used an of upper case from 1973 mated to a bottom case of 1979.
Your Z1-KZ are so machined to precise standards that it works!
As long as you are the same crank pin size. And tranny size, no Mark II or GPZ tranny./
Just do it! then find out!

The 100 motor is a 78 kz1000 while the cases are 73 z1 900. From the APE article, it seems all should be good.,

Perhaps this next question should be put in the carb section. Assuming I go this route, and am basically mating the stock Z1 carbs with the 1000 engine, what jetting should I start with?

Cheers,
Ross

Carbs are your last worry!
If you get your engine together, that's all that counts.
900- 1000 don't matter, 26 mm carbs, 120 pilot's, 120 -125 mains, drop jet clip to bottom
and your running.

Galactica, everything should be Ok, however, there are a few of items that could cause some concern.
1. the Z1 uses a 2 coil spring on it's gear-change mechanism, whereas, the Z1000 uses a 3 coil spring, which is obviously bulkier and will causes the inner sprocket cover on the Z1 cases, not to seal. The Z1000 accommodates the spring by having a recess in its bottom casing. So, its simply a matter of using the z1 spring.
2 The Z1 casing usually provide for the 1015 barrels, but it's worth checking. I do know some cases have to machined out to take the larger barrel liners.
3. When finishing the Z1000 barrels to give the same "fin linished finish" as the Z1, you will find these fins are thinner and also have small dimples along the fin. Makes it a bit hard!

I would go for Z1R Mikuni "High-top" carbs.
Oh! don't bother with changing the exhaust studs, 8mm look the part anyway!

RegardZ

check top idler gear for valve cover fitment,z1 and kz1000 I believe are slightly different.ran into that problem before, depending on which valve cover you are going with.

Garn wrote: Galactica, everything should be Ok, however, there are a few of items that could cause some concern.
1. the Z1 uses a 2 coil spring on it's gear-change mechanism, whereas, the Z1000 uses a 3 coil spring, which is obviously bulkier and will causes the inner sprocket cover on the Z1 cases, not to seal. The Z1000 accommodates the spring by having a recess in its bottom casing. So, its simply a matter of using the z1 spring.
2 The Z1 casing usually provide for the 1015 barrels, but it's worth checking. I do know some cases have to machined out to take the larger barrel liners.
3. When finishing the Z1000 barrels to give the same "fin linished finish" as the Z1, you will find these fins are thinner and also have small dimples along the fin. Makes it a bit hard!

I would go for Z1R Mikuni "High-top" carbs.
Oh! don't bother with changing the exhaust studs, 8mm look the part anyway!

RegardZ

You could have the 900 cylinder bored and put the 1000 sleeves dropped into it if you really want to be sneaky

With respect to boring the 900 barrels to accept the 1000 pistons, my understanding is that it can be done, but that it is the maximum size they can be bored.

Would there be any issues other than upper case clearance? The upper case can be machined to accommodate the bigger diameter of the barrels.

With the cylinder walls being that thin, are there any heat related issues?

Regarding the Z1 gear change double spring spring, I have a unit I can use.

I agree the carburration is the last thing to worry about. I just get ahead of myself sometimes.

I dont like seeing any sleeve being bored to its maximum size myself ,ive seen too many good engines turned into door stops in cars and bikes due lack of support in cylinder walls as motor heats up they turn to more of an egg than a round cylinder. :sick:
Now the pros will come on and tell me Im wrong! :woohoo:

I have a spare output shaft and gears off a 76 900 that I want to swap out for the output shaft and gears on my spare 77 1000 motor, should work right ?

JD

wireman wrote: I dont like seeing any sleeve being bored to its maximum size myself ,ive seen too many good engines turned into door stops in cars and bikes due lack of support in cylinder walls as motor heats up they turn to more of an egg than a round cylinder. :sick:
Now the pros will come on and tell me Im wrong! :woohoo:

:kiss: