depends on what equipment u have to work with and how carefull u are , cutting the bottom of the sleeve shoulder is the easiest, but every time u change cyls u have to match the new to the old.  the cyl is problt tapered so u should use an expanding mandrel

to cut the Case i use a 4 jaw chuck   and a piece of aluminum big enough the mount the engine on the end like u were mounting it in the plane,  put the setup in the 4 jaw chuck and indicate it with an indicator now the important part,  remove the case and take a skim cut on the fixture ,remount Case and finish indicating to zero run out  use a small sharp tool  and remove the amount u want to take off .when done put a small chanfer on the edge so it wont bind the case.

the more back pressure u have ,the more it affects the sub piston induction,  when we were kids a friend of mine cut the wrong side of a racing engine and u could see the rod under the piston and it ran fine  hope this helps

dont forget that u need to raise the head the same amout that u dropped the sleeve

 

Ok got that done and exhaust came in right at 160 but the transfers are now 117. Open face transfer timing is usually 125 right?

MM

Did some bench testing and it's down 1,000 rpm from my GO25. Got the tool made to mark the line and some diamond cutters to break through the chrome. I'll let you know how it goes.


MM