I discovered that Meng make nuts and bolts for scratchbuilding, I only wish I had found this out earlier, the grey ones are Meng the tan coloured ones are my own heat formed items.

Here is the finished compressor head with Meng nuts and bolts added. 

In my hand to give some idea of the size. 

I added some copper wire for the pressure hoses that run to the cylinder heads. 

Looking into the engine compartment.

Here are the spark plug fittings in place, also seen is the wiring harness and the way it links to the magneto.

This is the early construction of the compressor head. 

Some tube was turned down and the fins were made from 1mm styrene with holes drilled out through the centers. The discs were evenly spaced and glued in place.   

Here some more work has been done on the compressor head. 

A close up of the outlet pipe attachments. 

The top of the head.

After a long absence here are some updates. The nuts and bolts that hold the tank together are made up from a nut and a narrow lock nut. To make each one of these would be time consuming so I made a silicone rubber mold cast some for now.

The spark plug suppressors are also being cast as there are 12 of them. 

Here are a full set plus a few extras just in case.