I keep hearing references to the 'Bald John' stack, which, as far as I can tell is a fairly typical 160/BE3/xxx and 55/160. This is standard fare for a UK PX200 with a 24/24E carb. Now that I'm experimenting with a 140AC in conjunction with the BE3 and smaller main jets than I've grown accustomed to, I'm starting to see good results (this on a 200+cc engine). Is the Bald John stack essentially a thing of the past, or does it still apply to certain setups? It seems that the key here is the modifications made to the carb, notably the drilling of the passage between float bowl and main stack channel. Was this not done by many people until fairly recently?
As usual, I may be missing something.