Yes. Definately shouldn't have a problem warm and if you were fine before opening up the pipes smaller jets are not the answer.With my set up and altitude I am running 48s and 2 1/2 turns Starts fine just need to tweek a little st smooth out the idle. My open pipes are not that much less restricted than your drilled pipes. From my point of view I think play with the mixture screws. The shimmed needle shouldn't play any role in starting with throttle fully closed.

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