Double sleeves on 903?

[RC900]

Hi There!

I have an extra 903 block I was supposed to change the wiseco sleeves to it. But, but... I took these old barrels under investigation, and I noticed that there is some kind of outer sleeve on the barrel... Is this normal? I mean, the inner barrel seems to be the same size as these wiseco sleeves I have, but is there supposed be this kind of outer sleeve between the inner sleeve and the aluminium part of barrels? By reason or another, I have not never noticed that kind of "attachment" on the z1 barrles before... But I cannot be sure, it's long time since I've teared a Z1 engine apart and I just do not remember this kind of setup. Please, check the picture to see if this double sleeved barrel. Is it supposed to be built this way, or has somebody double sleeved this barrel before to get the 903 sleeves fit there?



Yours,

-RC900-

[zed1015]

Certainly not standard.
Common practice on old brit cast iron barrels but a bit dodgy if there isn't a lip on the top side to prevent the liner from dropping ?
Maybe it's a 1000 block and someones pressed the 900 sleeves into overbored 1000 sleeves or something like ( does the block have '903' Stamped rather than cast to indicate a restamped 1000 block)
Lots of possible explanations.
You really need the liners out to see if the block has been bored also.

[RC900]

Damn, that's what I was afraid of Thank you Zed1015

The barrel has 903 stamped on it and it looks original text, so maybe somebody has just changed bigger sleeves on it, and decided to use standard sleeves after that. Do I need a replacement 73 - 76 barrel, or is the std sleeve size the same on the z1000 as well?

[zed1015]

You will need a 900 block if wishing to fit std 900 liners.
1000 liners are bigger diameter.
Are the wiseco liners part of a kit just to re-sleeve back to std 66mm bore?
If they are part of a 1015/1045 or 1075 bigbore kit then the liners in those kits require the 900 block to be bored for them to fit but they do drop straight in to the 1000 blocks as they are in fact 1000 spec liners.

[RC900]

I guess my liners are just standard z1 liners, just bored for 70mm wiseco pistons. The outer diameter of the sleeves is about 74,5 mm. So I got to find a 903 block with 74,5mm sleeve holes, or std z1000 block which might be even more difficult to find.
I'd like to shout out loud, now...