yes I see what you mean by a plain bearing now, I've never had conrod issues in the past, mainly bearing corroison problems so fingers crossed with this new converison. I've just bench run the engine to see how it operates for now. I'm going to make a bracket to support the carburator, a piece of light aluminum should be ok as the cylinder will grow with heat, I quess 0.005" or so won't cause problems.

http://en.wikipedia.org/wiki/Polyoxymethylene "Acetal" spelt with a "e", my mistake. As far as thermal properties are concerned there are better plastics available. Acetal is very easy to cut and work with and the fact that I had some on hand. If I find my brass plate reaches high temperatures I will most likely make a new insulator.

I have no real gasket, just a thin layer of exhaust gasket sealant on the carb side, nothing on the brass plate side.

As far as RPM readings go, I have no tacho as of yet, but will sort one out.