To actually make these things work you need precise measurements. You'd need to know how your setup was working and doing what to what would effect it.
I.e. more air. How much air? How much fuel is needed to compensate it. At peak power is there enough fuel to air? Is there too much? How can I adjust this? What's the compression like. How much fuel is it actually burning? How much oil is it burning? Is the exhaust creating forced induction as it should. Or is it restrictive.
Some friends used a tool like this to bore out a carb for a 50cc. Im not shure how it worked though :P, Dont see any reasons for a bunch of accurate messurements tough. You bore it up. Fit it onto the engine. Start it and run it a bit then take out the plug too see its color. if the color is too light you put in a bigger jet untill the color is right.
only problem with boring out a carb is the venturi will be out of 'harmony' with the throat (the bit thats been bored out). the larger you go the more out of harmony it becomes.
it works if you dont bore it out too big
look at graham bells 4 stroke tuning in the carburation chapter
