I picked this 104 Allstate up last year, my third pre-1954 Allstate i own. it's a bit rough, but i love it and it really tells a story. They top end was seized and with the help of my Oxy-Acetylene torch and a block of wood, i should it who was boss. Now, there are no after market cylinders for these pre-1954 single port engines. . . none, so you have to be real careful getting things apart.
well, it was never soft seized believe it or not, it was oxidized. the conrod and bearings would not move at all.
i have cleaned up the cylinder with a light hone and am using the standard size piston. The exhaust and inlet are both cleaned up. New crank shaft with the additional of a needle bearing for the small end; original came with a brass bushing.
Last three pics may be new to a few of you on this board. Single port engine before i mounted the cylinder; yes, one big port. Fully CNC machined high compression that a friends makes is a nice additional to the original cylinder. Last pic is interesting: i machined an original flywheel to fit a Vespatronic ignition; fit and finish looks stock.
enjoy the pics.