The book also calls for the idle and main needles to be set at 1 turn out as a starting point .
How big is the throat of your MT57 ?
I tried an MT48A that has a throat size very close to the OEM MT1 size , but I couldn't get that to work well . The MT9B that I have mounted now , works much better . It has a much smaller throat size , by almost half .
Along with the smaller throat size , I have tried different amounts of fuel meter tube 'wall' holes . I'm currently running a total of 4 holes . That exactly half the amount used in the OEM MT1 carbs as well as the replacement Carter carbs .