Gents,
I couldn't resist borrowing this post from the BritBikeForum. I don't believe there are any copyright issues to be concerned with, however, as always, I rely on our administrator to make the determination.
Richard
Ok here are some pictures of the ream;
The piece with the cone screws onto the handle of the ream and the cone slides up and down and the ream turns inside it. This ream is 1.5" and bigger but seems to adj down a little from that. A smaller ream would have a smaller cone and need perhaps something made to fit into the D/Side case. As it is this larger cone fits tightly into the old oil seal, for those who think that may be too imprecise something could be made, however the seal seems to work fine and that end of the ream stays well held.
The ream adjusts by the two collars that can be turned to move the blades along the slots in the shaft that are tapered.
The ream makes for a very square hole, and the process would be made much simpler with inside and outside mics, so you could slowly approach correct size. You can guess clearence probably quite good if you remove the oil pump studs and test the crank from the outside and slowly creep it up. The ream can be removed and re-inserted without unbolting the cases. Once the crank drops in, and is only in the bush, the amount it rocks will indicate clearance. The one I did some years ago hardly rocked, but when in the motor, in both bearings, it would spin very freely, indicating good alignment.