The carb cleaners available today just don’t work as well as the toxic stuff of bygone years. In many ways this is a good thing but not so much when trying to clean pilot jets. The Dellorto carbs can have long, thin pilot jets which are even worse. I was doing a google-search for any new ideas and found an interesting recommendation. I got the stuff and dropped the recalcitrant jets in and left them for a few hours. Thoroughly rinsed with water and popped them back into the carbs.
Transformation! Nice smooth idle and with a clean pick-up.
The miracle substance? Toilet bowl cleaner. Not the gel stuff but the thin, liquid kind. Cheap, plentiful and it works very well.
This is just for BRASS parts. Do NOT put your carb bodies, plastic or rubber parts in!