Z1R block to 76' KZ900 cases

I understaand I may have to bore the 900 cases to accept the 1015 Z1R block. My question is, how much clearance should there be between the bore in the cases and the sleeeves? Believe the sleeves std which I have had honed to 70.25mm.

Secondly, is the deck height of the Z1r block the same as the 900 block and/or the std 1015 block? Thanks.

I dry fit the block, and then hit the front of the cases with a die grinder if there is a clearance issue so that the block doesn't fit down over the engine dowels. There isn't any consistant measurement to be made... Clean up good afterwards as the grinder makes a mess inside the cases.

The deck height for the Z1R engine is the same as all the rest of the 73-80 engines I think.

Thanks WG. I had asked a similar question a short time ago but didn't ask for the clearance. Just didn't want the sleeves to expand and different rate from the cases and potentially damage either the sleeves or the cases.

Took a good dig around last night and attempted to "dry fit" the 1015 block. Cases Look as though they may have been slightly doctored at an earlier date by the PO. Cases will need very slight work on the back side of each opening as where the work was dome before, the inside face of the opening has been left at maybe 80 degrees to the case deck, rather than 90 degrees. So, the bottom of the case opening is a little less in diameter that the top of the opening and, as the sleeves drop in, they are forces forward by the lower part of the opening, thereby preventing the block from fitting over the dowels.

Hope this makes sense to someone?

Have also discovered that the crank is welded. Good news.

Aluminum has a higher coefficient of expansion than steel, so as the motor warms up the clearances will actually increase. In other words, if it's a tight fit cold then it will be a loose fit hot

Thanks Steell, I think that fully answers the question I was realy trying to ask in the first place.

Steve makes all this junk up cuz he knows we are all too dumb to know what he is talking about bwhahaha

BH- I did understand what you were saying. The holes that the sleeves fit in are not round nor do you have to whack away all the way around... only on the one side. A mini air die grinder and about 5 minutes of grinding and you will be in business. Just clean the mess inside... perhaps it would be best to do the grinding with the cases split and just work with the upper case half and the bottom sitting out of the way with the crank and tranny in it!

WG, I was attempting to avoid having to split the cases. Don't have any apparent leaks or nasty noises in or from the cases. I was going to stuff some clean, oil-soaked rags down the holes to catch the bits? Think this will work?