It is raining today, so I decided to give the Amal Monobloc 389/18 a good going over for my 1961 GF. It is in basically OK nick and has been running OK, but some misfiring and hesitation above idle prompted me to check the carby out whilst I have the bike apart. There are other issues with timing, oily exhaust etc, but I am eliminating other possibilities as I go.
I have a new slide which needed very minor fettling to fit nicely, new needle etc, but ensuring that the two small orifices (orifi?) which vent into the carby throat are CLEAN took my fancy.
![bright idea *bright idea*](https://www.a7a10.net/forum/Smileys/default/Bright_Idea.gif)
(A nose-picking emoji would be more apt if available).
My musings and measurements are attached.
Delighted to be shot down in flames.!!
Cheers Col