One advantage of the imported lathes with their flange mount is that the studs can quickly be removed from the backplate so the chuck can be clamped to the mill table. That is how I held the casting to drill the holes for the feet and cylinder head. I also added two holes for 3mm dowel pins front to back as I decided not to use a machining plate and the dowels would help with lining things up.

=

So with two bits of 3mm drill rod in the holes resting against the side of a T-slot the casting was set up to machine the top of the bearing housing that takes the oval shaped name plate, I added an angle plate against the side to resist the force of the cutter as I did not want to bend or break the casting.

=

While setup like this I also cleaned up the top of the cylinder, the 80mm indexable mill allowing me to get close enough without the quill hitting the overhanging bearing housing.

=

The instructions suggest using a 1" countersink to chamfer the top of the cylinder but as I don't have one that big I just managed with a boring head and tool ground at 45degrees.

=

With two drill bits poked into the feet holes resting on parallels the base was clamped to an angle plate. To locate the centre line of the cylinder I turned up a close fitting plug and touched off each side of that; heights were easy enough touching off the angle plate.

=

The bearing housing could then be drilled and reamed 1/2", I added some aluminium packets at the bottom to stop any deflection from drilling pressure.

=

The casting was then rotated 90deg, and with pins in the dowel holes again lined up, to do the exhaust and spark plug contact holes

=

Then rotated 180 degrees to drill and tap for the spark plug.

=

Finally two angle plates were cobbled together so the casting could be held at a suitable angle to drill and tap for a grub screw to retain the exhaust which has to fit between two of the sloping cooling fins.

=

just enough done for a trial assembly.

Part two here  Part four here