Well if the carbs are refurbished, these holes should be clean and open in the right diameter - you don´t have to dismentle the carbs for checking those holes - just take out the four selenoids and if the carbs are monted on the engine, take a mirror and good light and check through the selenoid holes. The bypass holes are well visable through the selenoid holes.
Sometime I found one of the holes blocked by some material like silicone, used when the components have been assembled - such things can be removed by compressed air.
When I´ve got my Pinz, at the beginning, I had to clean these holes and also idle and main jets from time to time because the engine started to run poor in idle and slightly above.
When I take out the sparks for some reason I always check the spark plug face to detect any blockage in the carbs and on which cylinder I have to check (for this reason I have marked my sparks from 1 - 4).
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