mk 1 amal pilot jet

I want to fit a pilot jet into the original vacant hole after drilling and removing the fixed tube pilot. it is on. a mk1 Amal Atlas 750 engine in the P11. twin carbs are fitted. what size pilot jet should I use as there are various different sizes available. thanks in advance

25 was the default for 4 strokes, you may have some issues with the pilot jet being in the vacant hole as that was for 2 strokes. After the introduction of the Concentric the 4 stroke pilot jet was quickly moved from the vacant hole to the bush due to issues on the Triumph 500 twin.