Cylinders-too far gone?

all,
heres the other thing..
measured the cylinders and pistons last night, taper and out of round measurements all ok, but on one cylinder the wall to piston clearance is .0052, which is way big.
The problem is that the cylinder is a 900 bored to 70mm, exactly: this cylinder is 2.7595 (70.09mm) and the piston is 2.7543. (there was another that had .004 clearance, but you get the picture)
I know from looking at some of APE Jay's posts that the 1045 is too big for this cylinder, reliably.
Are there any other options other than getting another 900 cylinder and boring out to 70mm?
I dont want to have to bore out the case to get a 1000 cylinder in there, 1015 is plenty for me...
Thanks!

How about a one size over KZ1000 oem piston set?
I am not sure on availability but I believe you
could safely go that big.

if the cyls are not out of round I think you can get a set of pistons in a custom size, I know we did that on some race car motors that were limited on bore by rules.
you might send wisco a e mail and ask if they can do it and what the cost would be

If the cylinder is "to size" already? and not too "messed up"? You could look for a set of used 1015 pistons because what you describe the pistons are worn out too. This is "not the right way" at all, just cheap and easy. I think you already know what needs to be done here: time and $. No "magic cure" for this. Parts replacement job. It all depends on how "right" you want it to be.

all,
it seems like if I am gonna go thru a whole lot of trouble, i might as well do it right..probably another 900 cylinder from ebay or something, and then 1015 wiseco or sim pistons. that way i could finish it up to fit the new pistons right..
does anybody know if a 1000 cylinder set will fit into the block of the 900, or does that need to be bored out as well?
gettin tired of takin it apart over and over, but, you know, i am gettin faster at it...i bet now if you showed me a bag of bolts i could probably tell you where they go!....:S

The 76 and 77 900 cases are the exact same as the 1000 cases(up to 79)...so yes You can use a set of 1000 jugs on the 900 engine.
A lot of Guys have done it.

Sandy, the cases are the same outside dimension buy when you try and fit a 1015cc cylinder on the 903cc block, it generally won't fit without some grinding. You don't have to "bore" the cases... just grind them some in the area where the sleeves fit. The earlier KZ1000 sleeves fit easier than the later (79 on?) and less grinding is needed but I have had to grind every one I have fitted (a couple dozen I guess). You can tell a 79 cylinder because there is no little groove for an oring... the orange oring you fit for oil seal on the earlier blocks.

george,
this is good news...where do you need to grind them...do you think i can do this while the block is together? If it's only a small amount of grinding then i can block off the case from any grinding chips/etc.
Also, those orange o-rings seem never to fit well..how important are they, and could an ill fitting one be causing some of my smoking problems, i.e #4 is burning oil...
Thanks George and Sandy...
K

wiredgeorge wrote:

Sandy, the cases are the same outside dimension buy when you try and fit a 1015cc cylinder on the 903cc block, it generally won't fit without some grinding. You don't have to "bore" the cases... just grind them some in the area where the sleeves fit. The earlier KZ1000 sleeves fit easier than the later (79 on?) and less grinding is needed but I have had to grind every one I have fitted (a couple dozen I guess). You can tell a 79 cylinder because there is no little groove for an oring... the orange oring you fit for oil seal on the earlier blocks.

Hmmm...I just checked with the Kawi cross ref program...here's what I got.(see pic)
I'm not saying You're wrong George...not at all.
I've got a 900 out in the back yard that I'm pretty sure had 1000 jugs on it when I tore the top end off,so I'll look later to see if THAT Guy did any grinding to the cases.
I know others have done the exact same thing,but honestly...I can't remember if they had to(or mentioned)do any clearance grinding.:huh:

hey sandy, where can i access that x-ref program?

Sandy wrote:

wiredgeorge wrote:

Sandy, the cases are the same outside dimension buy when you try and fit a 1015cc cylinder on the 903cc block, it generally won't fit without some grinding. You don't have to "bore" the cases... just grind them some in the area where the sleeves fit. The earlier KZ1000 sleeves fit easier than the later (79 on?) and less grinding is needed but I have had to grind every one I have fitted (a couple dozen I guess). You can tell a 79 cylinder because there is no little groove for an oring... the orange oring you fit for oil seal on the earlier blocks.

When Kaw would upgrade an old part they would crossreference that old part to the new number but it may not be the same exact part as the old number. For example when original 73 (black) cases got updated only (silver) cases were available from the Kaw factory. It is quite possible that some of the later replacement 900 cases would fit 1000 jugs? However this was not the norm for original 900 cases. Most 900 cases need a little bit of grinding to fit 1000 jugs.

I am compulsed to respond to this thread. I have a 1000 motor (1977 vintage) with a cases that need to be replaced (too many stripped side cover holes), so I picked a a good set of Z1B cases for an eventual swap out using every thing from the 1000 motor. I tried to fit my 1000 jugs to these 900 cases and they don't fit. Thus, 1000 jugs are not a 'drop-in' and must be ground to fit. I haven't done it yet so I can't tell you where the grinding must be other than it is supposedly a fairly minor fix.