Just maybe this could go some way toward explaining the phenomenon of A10 induction bias. I recently removed my carburettor in order to give it a thorough clean, and while I was at it, I thought that it would be a good idea to renew the manifold gaskets and insulating spacer. To this end I bought a set of genuine new Amal gaskets and a spacer. I put everything back together and to my consternation the left hand cylinder was now running lean, and the right cylinder appeared to be a bit on the rich side. Before I stripped everything down both cylinders were more or less running equal if the plug colour was anything to go buy. So, what could be going on then? What could be the reason for this? Well, it turned out to be the new gaskets and insulating spacer. See the two pictures. The new gaskets and spacer superimposed on the old gaskets. As you can see the new gaskets were masking the inlet manifold. To cut a long story short I refitted the carb using the old used gaskets and spacer, and hey presto! both cylinders are now running the same. I know, I know, I should have checked before fitting, but I naively assumed (wrongly) as it happened that the new gaskets would be identical. It just goes to show what happens when you do that.
